Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Daniel Vetter]

On Mon, May 08, 2017 at 11:13:37AM +0100, Jose Abreu wrote:
> Hi Daniel,
> 
> 
> On 08-05-2017 08:50, Daniel Vetter wrote:
> > On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
> >> This changes the connector probe helper function to use the new
> >> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
> >> validate the modes.
> >>
> >> The new callbacks are optional so the behaviour remains the same
> >> if they are not implemented. If they are, then the code loops
> >> through all the connector's encodersXcrtcs and calls the
> >> callback.
> >>
> >> If at least a valid encoderXcrtc combination is found which
> >> accepts the mode then the function returns MODE_OK.
> >>
> >> Signed-off-by: Jose Abreu 
> >> Cc: Carlos Palminha 
> >> Cc: Alexey Brodkin 
> >> Cc: Ville Syrjälä 
> >> Cc: Daniel Vetter 
> >> Cc: Dave Airlie 
> >> Cc: Andrzej Hajda 
> >> Cc: Archit Taneja 
> > A few comments below.
> > -Daniel
> 
> Thanks for the review!
> 
> >
> >> ---
> >>  drivers/gpu/drm/drm_probe_helper.c | 71 
> >> +++---
> >>  1 file changed, 67 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> >> b/drivers/gpu/drm/drm_probe_helper.c
> >> index 1b0c14a..bf19f82 100644
> >> --- a/drivers/gpu/drm/drm_probe_helper.c
> >> +++ b/drivers/gpu/drm/drm_probe_helper.c
> >> @@ -80,6 +80,67 @@
> >>return MODE_OK;
> >>  }
> >>  
> >> +static enum drm_mode_status
> >> +drm_mode_validate_connector(struct drm_connector *connector,
> >> +  struct drm_display_mode *mode)
> >> +{
> >> +  const struct drm_connector_helper_funcs *connector_funcs =
> >> +  connector->helper_private;
> >> +  struct drm_device *dev = connector->dev;
> >> +  uint32_t *ids = connector->encoder_ids;
> >> +  enum drm_mode_status ret = MODE_OK;
> >> +  unsigned int i;
> >> +
> >> +  /* Step 1: Validate against connector */
> >> +  if (connector_funcs && connector_funcs->mode_valid)
> >> +  ret = connector_funcs->mode_valid(connector, mode);
> >> +
> >> +  if (ret != MODE_OK)
> >> +  return ret;
> >> +
> >> +  /* Step 2: Validate against encoders and crtcs */
> >> +  for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> >> +  struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
> >> +  const struct drm_encoder_helper_funcs *encoder_funcs;
> >> +  struct drm_crtc *crtc;
> >> +
> >> +  if (!encoder)
> >> +  continue;
> >> +
> >> +  encoder_funcs = encoder->helper_private;
> >> +  if (encoder_funcs && encoder_funcs->mode_valid)
> >> +  ret = encoder_funcs->mode_valid(encoder, mode);
> >> +  else
> >> +  ret = MODE_OK; /* encoder accepts everything */
> >> +
> >> +  /* No point in continuing for crtc check as this encoder will
> >> +   * not accept the mode anyway. If all encoders reject the mode
> >> +   * then, at exit, ret will not be MODE_OK. */
> >> +  if (ret != MODE_OK)
> >> +  continue;
> > I think we should validate encoders against connector->possible_ids here.
> > Might be that not many drivers fill this out correctly, and in case fixing
> > that is much work, perhaps as a follow-up. But would be good to at least
> > help look down that part of uapi a bit more.
> 
> I'm sorry but I'm not following you here (I think I need more
> coffee :)).
> 
> What do you mean by connector->possible_ids ? Is this something
> new ? Because I didn't find anything in my tree and I'm based on
> today's drm-next from Dave.

Oops, I guess I was on an old tree or whatever by accident. I meant
drm_connector->encoder_ids, that limits the encoders you can use on a
crtc. For many drivers there's only one.

> > This isn't checked within atomic and legacy helpers since we assume that
> > ->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
> > ...
> >
> >> +
> >> +  drm_for_each_crtc(crtc, dev) {
> >> +  const struct drm_crtc_helper_funcs *crtc_funcs;
> >> +
> >> +  if (!drm_encoder_crtc_ok(encoder, crtc))
> >> +  continue;
> > We check this one here already in both atomic and legacy helpers, so all
> > drivers should get this right.
> 
> But drm_for_each_crtc() iterates over all crtc from a device and
> some crtcs may only be used by specific encoders (by setting
> encoder->possible_crtcs), right ? We need to iterate only over
> the encoder's crtc we want to validate.

This was a comment about ->encoder_ids, since we don't validate that in
the atomic helpers (but instead rely on ->(atomic_)best_encoder to give us
the right encoder) validating here in this function might be a problem and
uncover driver bugs. But for 

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Daniel Vetter]

On Mon, May 08, 2017 at 11:13:37AM +0100, Jose Abreu wrote:
> Hi Daniel,
> 
> 
> On 08-05-2017 08:50, Daniel Vetter wrote:
> > On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
> >> This changes the connector probe helper function to use the new
> >> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
> >> validate the modes.
> >>
> >> The new callbacks are optional so the behaviour remains the same
> >> if they are not implemented. If they are, then the code loops
> >> through all the connector's encodersXcrtcs and calls the
> >> callback.
> >>
> >> If at least a valid encoderXcrtc combination is found which
> >> accepts the mode then the function returns MODE_OK.
> >>
> >> Signed-off-by: Jose Abreu 
> >> Cc: Carlos Palminha 
> >> Cc: Alexey Brodkin 
> >> Cc: Ville Syrjälä 
> >> Cc: Daniel Vetter 
> >> Cc: Dave Airlie 
> >> Cc: Andrzej Hajda 
> >> Cc: Archit Taneja 
> > A few comments below.
> > -Daniel
> 
> Thanks for the review!
> 
> >
> >> ---
> >>  drivers/gpu/drm/drm_probe_helper.c | 71 
> >> +++---
> >>  1 file changed, 67 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> >> b/drivers/gpu/drm/drm_probe_helper.c
> >> index 1b0c14a..bf19f82 100644
> >> --- a/drivers/gpu/drm/drm_probe_helper.c
> >> +++ b/drivers/gpu/drm/drm_probe_helper.c
> >> @@ -80,6 +80,67 @@
> >>return MODE_OK;
> >>  }
> >>  
> >> +static enum drm_mode_status
> >> +drm_mode_validate_connector(struct drm_connector *connector,
> >> +  struct drm_display_mode *mode)
> >> +{
> >> +  const struct drm_connector_helper_funcs *connector_funcs =
> >> +  connector->helper_private;
> >> +  struct drm_device *dev = connector->dev;
> >> +  uint32_t *ids = connector->encoder_ids;
> >> +  enum drm_mode_status ret = MODE_OK;
> >> +  unsigned int i;
> >> +
> >> +  /* Step 1: Validate against connector */
> >> +  if (connector_funcs && connector_funcs->mode_valid)
> >> +  ret = connector_funcs->mode_valid(connector, mode);
> >> +
> >> +  if (ret != MODE_OK)
> >> +  return ret;
> >> +
> >> +  /* Step 2: Validate against encoders and crtcs */
> >> +  for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> >> +  struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
> >> +  const struct drm_encoder_helper_funcs *encoder_funcs;
> >> +  struct drm_crtc *crtc;
> >> +
> >> +  if (!encoder)
> >> +  continue;
> >> +
> >> +  encoder_funcs = encoder->helper_private;
> >> +  if (encoder_funcs && encoder_funcs->mode_valid)
> >> +  ret = encoder_funcs->mode_valid(encoder, mode);
> >> +  else
> >> +  ret = MODE_OK; /* encoder accepts everything */
> >> +
> >> +  /* No point in continuing for crtc check as this encoder will
> >> +   * not accept the mode anyway. If all encoders reject the mode
> >> +   * then, at exit, ret will not be MODE_OK. */
> >> +  if (ret != MODE_OK)
> >> +  continue;
> > I think we should validate encoders against connector->possible_ids here.
> > Might be that not many drivers fill this out correctly, and in case fixing
> > that is much work, perhaps as a follow-up. But would be good to at least
> > help look down that part of uapi a bit more.
> 
> I'm sorry but I'm not following you here (I think I need more
> coffee :)).
> 
> What do you mean by connector->possible_ids ? Is this something
> new ? Because I didn't find anything in my tree and I'm based on
> today's drm-next from Dave.

Oops, I guess I was on an old tree or whatever by accident. I meant
drm_connector->encoder_ids, that limits the encoders you can use on a
crtc. For many drivers there's only one.

> > This isn't checked within atomic and legacy helpers since we assume that
> > ->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
> > ...
> >
> >> +
> >> +  drm_for_each_crtc(crtc, dev) {
> >> +  const struct drm_crtc_helper_funcs *crtc_funcs;
> >> +
> >> +  if (!drm_encoder_crtc_ok(encoder, crtc))
> >> +  continue;
> > We check this one here already in both atomic and legacy helpers, so all
> > drivers should get this right.
> 
> But drm_for_each_crtc() iterates over all crtc from a device and
> some crtcs may only be used by specific encoders (by setting
> encoder->possible_crtcs), right ? We need to iterate only over
> the encoder's crtc we want to validate.

This was a comment about ->encoder_ids, since we don't validate that in
the atomic helpers (but instead rely on ->(atomic_)best_encoder to give us
the right encoder) validating here in this function might be a problem and
uncover driver bugs. But for drm_encoder_crtc_ok there's no such risk, so
this is safe.

I was simply dumping my thoughts while reviewing, the code is all good :-)

Cheers, Daniel
-- 
Daniel Vetter
Software Engineer, Intel 

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Jose Abreu]

Hi Daniel,


On 08-05-2017 08:50, Daniel Vetter wrote:
> On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
>> This changes the connector probe helper function to use the new
>> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
>> validate the modes.
>>
>> The new callbacks are optional so the behaviour remains the same
>> if they are not implemented. If they are, then the code loops
>> through all the connector's encodersXcrtcs and calls the
>> callback.
>>
>> If at least a valid encoderXcrtc combination is found which
>> accepts the mode then the function returns MODE_OK.
>>
>> Signed-off-by: Jose Abreu 
>> Cc: Carlos Palminha 
>> Cc: Alexey Brodkin 
>> Cc: Ville Syrjälä 
>> Cc: Daniel Vetter 
>> Cc: Dave Airlie 
>> Cc: Andrzej Hajda 
>> Cc: Archit Taneja 
> A few comments below.
> -Daniel

Thanks for the review!

>
>> ---
>>  drivers/gpu/drm/drm_probe_helper.c | 71 
>> +++---
>>  1 file changed, 67 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
>> b/drivers/gpu/drm/drm_probe_helper.c
>> index 1b0c14a..bf19f82 100644
>> --- a/drivers/gpu/drm/drm_probe_helper.c
>> +++ b/drivers/gpu/drm/drm_probe_helper.c
>> @@ -80,6 +80,67 @@
>>  return MODE_OK;
>>  }
>>  
>> +static enum drm_mode_status
>> +drm_mode_validate_connector(struct drm_connector *connector,
>> +struct drm_display_mode *mode)
>> +{
>> +const struct drm_connector_helper_funcs *connector_funcs =
>> +connector->helper_private;
>> +struct drm_device *dev = connector->dev;
>> +uint32_t *ids = connector->encoder_ids;
>> +enum drm_mode_status ret = MODE_OK;
>> +unsigned int i;
>> +
>> +/* Step 1: Validate against connector */
>> +if (connector_funcs && connector_funcs->mode_valid)
>> +ret = connector_funcs->mode_valid(connector, mode);
>> +
>> +if (ret != MODE_OK)
>> +return ret;
>> +
>> +/* Step 2: Validate against encoders and crtcs */
>> +for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
>> +struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
>> +const struct drm_encoder_helper_funcs *encoder_funcs;
>> +struct drm_crtc *crtc;
>> +
>> +if (!encoder)
>> +continue;
>> +
>> +encoder_funcs = encoder->helper_private;
>> +if (encoder_funcs && encoder_funcs->mode_valid)
>> +ret = encoder_funcs->mode_valid(encoder, mode);
>> +else
>> +ret = MODE_OK; /* encoder accepts everything */
>> +
>> +/* No point in continuing for crtc check as this encoder will
>> + * not accept the mode anyway. If all encoders reject the mode
>> + * then, at exit, ret will not be MODE_OK. */
>> +if (ret != MODE_OK)
>> +continue;
> I think we should validate encoders against connector->possible_ids here.
> Might be that not many drivers fill this out correctly, and in case fixing
> that is much work, perhaps as a follow-up. But would be good to at least
> help look down that part of uapi a bit more.

I'm sorry but I'm not following you here (I think I need more
coffee :)).

What do you mean by connector->possible_ids ? Is this something
new ? Because I didn't find anything in my tree and I'm based on
today's drm-next from Dave.

>
> This isn't checked within atomic and legacy helpers since we assume that
> ->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
> ...
>
>> +
>> +drm_for_each_crtc(crtc, dev) {
>> +const struct drm_crtc_helper_funcs *crtc_funcs;
>> +
>> +if (!drm_encoder_crtc_ok(encoder, crtc))
>> +continue;
> We check this one here already in both atomic and legacy helpers, so all
> drivers should get this right.

But drm_for_each_crtc() iterates over all crtc from a device and
some crtcs may only be used by specific encoders (by setting
encoder->possible_crtcs), right ? We need to iterate only over
the encoder's crtc we want to validate.

>
>> +
>> +crtc_funcs = crtc->helper_private;
>> +if (!crtc_funcs || !crtc_funcs->mode_valid)
>> +return MODE_OK; /* crtc accepts everything */
>> +
>> +ret = crtc_funcs->mode_valid(crtc, mode);
>> +if (ret == MODE_OK)
>> +/* If we get to this point there is at least
>> + * one combination of encoder+crtc that works
>> + * for this mode. Lets return now. */
>> +return ret;
>> +}
>> +}
>> +
>> +return ret;
>> 

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Jose Abreu]

Hi Daniel,


On 08-05-2017 08:50, Daniel Vetter wrote:
> On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
>> This changes the connector probe helper function to use the new
>> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
>> validate the modes.
>>
>> The new callbacks are optional so the behaviour remains the same
>> if they are not implemented. If they are, then the code loops
>> through all the connector's encodersXcrtcs and calls the
>> callback.
>>
>> If at least a valid encoderXcrtc combination is found which
>> accepts the mode then the function returns MODE_OK.
>>
>> Signed-off-by: Jose Abreu 
>> Cc: Carlos Palminha 
>> Cc: Alexey Brodkin 
>> Cc: Ville Syrjälä 
>> Cc: Daniel Vetter 
>> Cc: Dave Airlie 
>> Cc: Andrzej Hajda 
>> Cc: Archit Taneja 
> A few comments below.
> -Daniel

Thanks for the review!

>
>> ---
>>  drivers/gpu/drm/drm_probe_helper.c | 71 
>> +++---
>>  1 file changed, 67 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
>> b/drivers/gpu/drm/drm_probe_helper.c
>> index 1b0c14a..bf19f82 100644
>> --- a/drivers/gpu/drm/drm_probe_helper.c
>> +++ b/drivers/gpu/drm/drm_probe_helper.c
>> @@ -80,6 +80,67 @@
>>  return MODE_OK;
>>  }
>>  
>> +static enum drm_mode_status
>> +drm_mode_validate_connector(struct drm_connector *connector,
>> +struct drm_display_mode *mode)
>> +{
>> +const struct drm_connector_helper_funcs *connector_funcs =
>> +connector->helper_private;
>> +struct drm_device *dev = connector->dev;
>> +uint32_t *ids = connector->encoder_ids;
>> +enum drm_mode_status ret = MODE_OK;
>> +unsigned int i;
>> +
>> +/* Step 1: Validate against connector */
>> +if (connector_funcs && connector_funcs->mode_valid)
>> +ret = connector_funcs->mode_valid(connector, mode);
>> +
>> +if (ret != MODE_OK)
>> +return ret;
>> +
>> +/* Step 2: Validate against encoders and crtcs */
>> +for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
>> +struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
>> +const struct drm_encoder_helper_funcs *encoder_funcs;
>> +struct drm_crtc *crtc;
>> +
>> +if (!encoder)
>> +continue;
>> +
>> +encoder_funcs = encoder->helper_private;
>> +if (encoder_funcs && encoder_funcs->mode_valid)
>> +ret = encoder_funcs->mode_valid(encoder, mode);
>> +else
>> +ret = MODE_OK; /* encoder accepts everything */
>> +
>> +/* No point in continuing for crtc check as this encoder will
>> + * not accept the mode anyway. If all encoders reject the mode
>> + * then, at exit, ret will not be MODE_OK. */
>> +if (ret != MODE_OK)
>> +continue;
> I think we should validate encoders against connector->possible_ids here.
> Might be that not many drivers fill this out correctly, and in case fixing
> that is much work, perhaps as a follow-up. But would be good to at least
> help look down that part of uapi a bit more.

I'm sorry but I'm not following you here (I think I need more
coffee :)).

What do you mean by connector->possible_ids ? Is this something
new ? Because I didn't find anything in my tree and I'm based on
today's drm-next from Dave.

>
> This isn't checked within atomic and legacy helpers since we assume that
> ->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
> ...
>
>> +
>> +drm_for_each_crtc(crtc, dev) {
>> +const struct drm_crtc_helper_funcs *crtc_funcs;
>> +
>> +if (!drm_encoder_crtc_ok(encoder, crtc))
>> +continue;
> We check this one here already in both atomic and legacy helpers, so all
> drivers should get this right.

But drm_for_each_crtc() iterates over all crtc from a device and
some crtcs may only be used by specific encoders (by setting
encoder->possible_crtcs), right ? We need to iterate only over
the encoder's crtc we want to validate.

>
>> +
>> +crtc_funcs = crtc->helper_private;
>> +if (!crtc_funcs || !crtc_funcs->mode_valid)
>> +return MODE_OK; /* crtc accepts everything */
>> +
>> +ret = crtc_funcs->mode_valid(crtc, mode);
>> +if (ret == MODE_OK)
>> +/* If we get to this point there is at least
>> + * one combination of encoder+crtc that works
>> + * for this mode. Lets return now. */
>> +return ret;
>> +}
>> +}
>> +
>> +return ret;
>> +}
>> +
>>  static int drm_helper_probe_add_cmdline_mode(struct drm_connector 
>> *connector)
>>  {
>>  struct drm_cmdline_mode *cmdline_mode;
>> @@ -283,8 +344,10 @@ void 

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Daniel Vetter]

On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
> This changes the connector probe helper function to use the new
> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
> validate the modes.
> 
> The new callbacks are optional so the behaviour remains the same
> if they are not implemented. If they are, then the code loops
> through all the connector's encodersXcrtcs and calls the
> callback.
> 
> If at least a valid encoderXcrtc combination is found which
> accepts the mode then the function returns MODE_OK.
> 
> Signed-off-by: Jose Abreu 
> Cc: Carlos Palminha 
> Cc: Alexey Brodkin 
> Cc: Ville Syrjälä 
> Cc: Daniel Vetter 
> Cc: Dave Airlie 
> Cc: Andrzej Hajda 
> Cc: Archit Taneja 

A few comments below.
-Daniel

> ---
>  drivers/gpu/drm/drm_probe_helper.c | 71 
> +++---
>  1 file changed, 67 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> b/drivers/gpu/drm/drm_probe_helper.c
> index 1b0c14a..bf19f82 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -80,6 +80,67 @@
>   return MODE_OK;
>  }
>  
> +static enum drm_mode_status
> +drm_mode_validate_connector(struct drm_connector *connector,
> + struct drm_display_mode *mode)
> +{
> + const struct drm_connector_helper_funcs *connector_funcs =
> + connector->helper_private;
> + struct drm_device *dev = connector->dev;
> + uint32_t *ids = connector->encoder_ids;
> + enum drm_mode_status ret = MODE_OK;
> + unsigned int i;
> +
> + /* Step 1: Validate against connector */
> + if (connector_funcs && connector_funcs->mode_valid)
> + ret = connector_funcs->mode_valid(connector, mode);
> +
> + if (ret != MODE_OK)
> + return ret;
> +
> + /* Step 2: Validate against encoders and crtcs */
> + for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> + struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
> + const struct drm_encoder_helper_funcs *encoder_funcs;
> + struct drm_crtc *crtc;
> +
> + if (!encoder)
> + continue;
> +
> + encoder_funcs = encoder->helper_private;
> + if (encoder_funcs && encoder_funcs->mode_valid)
> + ret = encoder_funcs->mode_valid(encoder, mode);
> + else
> + ret = MODE_OK; /* encoder accepts everything */
> +
> + /* No point in continuing for crtc check as this encoder will
> +  * not accept the mode anyway. If all encoders reject the mode
> +  * then, at exit, ret will not be MODE_OK. */
> + if (ret != MODE_OK)
> + continue;

I think we should validate encoders against connector->possible_ids here.
Might be that not many drivers fill this out correctly, and in case fixing
that is much work, perhaps as a follow-up. But would be good to at least
help look down that part of uapi a bit more.

This isn't checked within atomic and legacy helpers since we assume that
->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
...

> +
> + drm_for_each_crtc(crtc, dev) {
> + const struct drm_crtc_helper_funcs *crtc_funcs;
> +
> + if (!drm_encoder_crtc_ok(encoder, crtc))
> + continue;

We check this one here already in both atomic and legacy helpers, so all
drivers should get this right.

> +
> + crtc_funcs = crtc->helper_private;
> + if (!crtc_funcs || !crtc_funcs->mode_valid)
> + return MODE_OK; /* crtc accepts everything */
> +
> + ret = crtc_funcs->mode_valid(crtc, mode);
> + if (ret == MODE_OK)
> + /* If we get to this point there is at least
> +  * one combination of encoder+crtc that works
> +  * for this mode. Lets return now. */
> + return ret;
> + }
> + }
> +
> + return ret;
> +}
> +
>  static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
>  {
>   struct drm_cmdline_mode *cmdline_mode;
> @@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
>   *  (if specified)
>   *- drm_mode_validate_flag() checks the modes against basic connector
>   *  capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
> - *- the optional _connector_helper_funcs.mode_valid helper can 
> perform
> - *  driver and/or hardware specific checks
> + *- the optional _connector_helper_funcs.mode_valid,
> + *   

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Daniel Vetter]

On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
> This changes the connector probe helper function to use the new
> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
> validate the modes.
> 
> The new callbacks are optional so the behaviour remains the same
> if they are not implemented. If they are, then the code loops
> through all the connector's encodersXcrtcs and calls the
> callback.
> 
> If at least a valid encoderXcrtc combination is found which
> accepts the mode then the function returns MODE_OK.
> 
> Signed-off-by: Jose Abreu 
> Cc: Carlos Palminha 
> Cc: Alexey Brodkin 
> Cc: Ville Syrjälä 
> Cc: Daniel Vetter 
> Cc: Dave Airlie 
> Cc: Andrzej Hajda 
> Cc: Archit Taneja 

A few comments below.
-Daniel

> ---
>  drivers/gpu/drm/drm_probe_helper.c | 71 
> +++---
>  1 file changed, 67 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> b/drivers/gpu/drm/drm_probe_helper.c
> index 1b0c14a..bf19f82 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -80,6 +80,67 @@
>   return MODE_OK;
>  }
>  
> +static enum drm_mode_status
> +drm_mode_validate_connector(struct drm_connector *connector,
> + struct drm_display_mode *mode)
> +{
> + const struct drm_connector_helper_funcs *connector_funcs =
> + connector->helper_private;
> + struct drm_device *dev = connector->dev;
> + uint32_t *ids = connector->encoder_ids;
> + enum drm_mode_status ret = MODE_OK;
> + unsigned int i;
> +
> + /* Step 1: Validate against connector */
> + if (connector_funcs && connector_funcs->mode_valid)
> + ret = connector_funcs->mode_valid(connector, mode);
> +
> + if (ret != MODE_OK)
> + return ret;
> +
> + /* Step 2: Validate against encoders and crtcs */
> + for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> + struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
> + const struct drm_encoder_helper_funcs *encoder_funcs;
> + struct drm_crtc *crtc;
> +
> + if (!encoder)
> + continue;
> +
> + encoder_funcs = encoder->helper_private;
> + if (encoder_funcs && encoder_funcs->mode_valid)
> + ret = encoder_funcs->mode_valid(encoder, mode);
> + else
> + ret = MODE_OK; /* encoder accepts everything */
> +
> + /* No point in continuing for crtc check as this encoder will
> +  * not accept the mode anyway. If all encoders reject the mode
> +  * then, at exit, ret will not be MODE_OK. */
> + if (ret != MODE_OK)
> + continue;

I think we should validate encoders against connector->possible_ids here.
Might be that not many drivers fill this out correctly, and in case fixing
that is much work, perhaps as a follow-up. But would be good to at least
help look down that part of uapi a bit more.

This isn't checked within atomic and legacy helpers since we assume that
->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
...

> +
> + drm_for_each_crtc(crtc, dev) {
> + const struct drm_crtc_helper_funcs *crtc_funcs;
> +
> + if (!drm_encoder_crtc_ok(encoder, crtc))
> + continue;

We check this one here already in both atomic and legacy helpers, so all
drivers should get this right.

> +
> + crtc_funcs = crtc->helper_private;
> + if (!crtc_funcs || !crtc_funcs->mode_valid)
> + return MODE_OK; /* crtc accepts everything */
> +
> + ret = crtc_funcs->mode_valid(crtc, mode);
> + if (ret == MODE_OK)
> + /* If we get to this point there is at least
> +  * one combination of encoder+crtc that works
> +  * for this mode. Lets return now. */
> + return ret;
> + }
> + }
> +
> + return ret;
> +}
> +
>  static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
>  {
>   struct drm_cmdline_mode *cmdline_mode;
> @@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
>   *  (if specified)
>   *- drm_mode_validate_flag() checks the modes against basic connector
>   *  capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
> - *- the optional _connector_helper_funcs.mode_valid helper can 
> perform
> - *  driver and/or hardware specific checks
> + *- the optional _connector_helper_funcs.mode_valid,
> + *   _crtc_helper_funcs.mode_valid and
> + *   _encoder_helper_funcs.mode_valid helpers can perform driver 
> and/or
> + *   hardware specific checks

I'd leave 2 bullets for 

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Jose Abreu]

Hi Ville,


On 04-05-2017 15:32, Ville Syrjälä wrote:
> On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
>> This changes the connector probe helper function to use the new
>> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
>> validate the modes.
>>
>> The new callbacks are optional so the behaviour remains the same
>> if they are not implemented. If they are, then the code loops
>> through all the connector's encodersXcrtcs and calls the
>> callback.
>>
>> If at least a valid encoderXcrtc combination is found which
>> accepts the mode then the function returns MODE_OK.
>>
>> Signed-off-by: Jose Abreu 
>> Cc: Carlos Palminha 
>> Cc: Alexey Brodkin 
>> Cc: Ville Syrjälä 
>> Cc: Daniel Vetter 
>> Cc: Dave Airlie 
>> Cc: Andrzej Hajda 
>> Cc: Archit Taneja 
>> ---
>>  drivers/gpu/drm/drm_probe_helper.c | 71 
>> +++---
>>  1 file changed, 67 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
>> b/drivers/gpu/drm/drm_probe_helper.c
>> index 1b0c14a..bf19f82 100644
>> --- a/drivers/gpu/drm/drm_probe_helper.c
>> +++ b/drivers/gpu/drm/drm_probe_helper.c
>> @@ -80,6 +80,67 @@
>>  return MODE_OK;
>>  }
>>  
>> +static enum drm_mode_status
>> +drm_mode_validate_connector(struct drm_connector *connector,
>> +struct drm_display_mode *mode)
>> +{
>> +const struct drm_connector_helper_funcs *connector_funcs =
>> +connector->helper_private;
>> +struct drm_device *dev = connector->dev;
>> +uint32_t *ids = connector->encoder_ids;
>> +enum drm_mode_status ret = MODE_OK;
>> +unsigned int i;
>> +
>> +/* Step 1: Validate against connector */
>> +if (connector_funcs && connector_funcs->mode_valid)
>> +ret = connector_funcs->mode_valid(connector, mode);
>> +
>> +if (ret != MODE_OK)
>> +return ret;
>> +
>> +/* Step 2: Validate against encoders and crtcs */
>> +for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
>> +struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
>> +const struct drm_encoder_helper_funcs *encoder_funcs;
>> +struct drm_crtc *crtc;
>> +
>> +if (!encoder)
>> +continue;
>> +
>> +encoder_funcs = encoder->helper_private;
>> +if (encoder_funcs && encoder_funcs->mode_valid)
>> +ret = encoder_funcs->mode_valid(encoder, mode);
>> +else
>> +ret = MODE_OK; /* encoder accepts everything */
> Since you already added the drm_bridge_mode_valid() helper, maybe add one
> for connectors, encoders and crtcs as well. Might keep the logic in this
> function a bit more clear on account of not having to check for the
> presence of the vfunc. Right now all three cases look slightly
> different from one another.

Ok, will add in next version. Thanks!

Best regards,
Jose Miguel Abreu

>
>> +
>> +/* No point in continuing for crtc check as this encoder will
>> + * not accept the mode anyway. If all encoders reject the mode
>> + * then, at exit, ret will not be MODE_OK. */
>> +if (ret != MODE_OK)
>> +continue;
>> +
>> +drm_for_each_crtc(crtc, dev) {
>> +const struct drm_crtc_helper_funcs *crtc_funcs;
>> +
>> +if (!drm_encoder_crtc_ok(encoder, crtc))
>> +continue;
>> +
>> +crtc_funcs = crtc->helper_private;
>> +if (!crtc_funcs || !crtc_funcs->mode_valid)
>> +return MODE_OK; /* crtc accepts everything */
>> +
>> +ret = crtc_funcs->mode_valid(crtc, mode);
>> +if (ret == MODE_OK)
>> +/* If we get to this point there is at least
>> + * one combination of encoder+crtc that works
>> + * for this mode. Lets return now. */
>> +return ret;
>> +}
>> +}
>> +
>> +return ret;
>> +}
>> +
>>  static int drm_helper_probe_add_cmdline_mode(struct drm_connector 
>> *connector)
>>  {
>>  struct drm_cmdline_mode *cmdline_mode;
>> @@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
>>   *  (if specified)
>>   *- drm_mode_validate_flag() checks the modes against basic connector
>>   *  capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
>> - *- the optional _connector_helper_funcs.mode_valid helper can 
>> perform
>> - *  driver and/or hardware specific checks
>> + *- the optional _connector_helper_funcs.mode_valid,
>> + *  _crtc_helper_funcs.mode_valid and
>> + *  

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Jose Abreu]

Hi Ville,


On 04-05-2017 15:32, Ville Syrjälä wrote:
> On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
>> This changes the connector probe helper function to use the new
>> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
>> validate the modes.
>>
>> The new callbacks are optional so the behaviour remains the same
>> if they are not implemented. If they are, then the code loops
>> through all the connector's encodersXcrtcs and calls the
>> callback.
>>
>> If at least a valid encoderXcrtc combination is found which
>> accepts the mode then the function returns MODE_OK.
>>
>> Signed-off-by: Jose Abreu 
>> Cc: Carlos Palminha 
>> Cc: Alexey Brodkin 
>> Cc: Ville Syrjälä 
>> Cc: Daniel Vetter 
>> Cc: Dave Airlie 
>> Cc: Andrzej Hajda 
>> Cc: Archit Taneja 
>> ---
>>  drivers/gpu/drm/drm_probe_helper.c | 71 
>> +++---
>>  1 file changed, 67 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
>> b/drivers/gpu/drm/drm_probe_helper.c
>> index 1b0c14a..bf19f82 100644
>> --- a/drivers/gpu/drm/drm_probe_helper.c
>> +++ b/drivers/gpu/drm/drm_probe_helper.c
>> @@ -80,6 +80,67 @@
>>  return MODE_OK;
>>  }
>>  
>> +static enum drm_mode_status
>> +drm_mode_validate_connector(struct drm_connector *connector,
>> +struct drm_display_mode *mode)
>> +{
>> +const struct drm_connector_helper_funcs *connector_funcs =
>> +connector->helper_private;
>> +struct drm_device *dev = connector->dev;
>> +uint32_t *ids = connector->encoder_ids;
>> +enum drm_mode_status ret = MODE_OK;
>> +unsigned int i;
>> +
>> +/* Step 1: Validate against connector */
>> +if (connector_funcs && connector_funcs->mode_valid)
>> +ret = connector_funcs->mode_valid(connector, mode);
>> +
>> +if (ret != MODE_OK)
>> +return ret;
>> +
>> +/* Step 2: Validate against encoders and crtcs */
>> +for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
>> +struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
>> +const struct drm_encoder_helper_funcs *encoder_funcs;
>> +struct drm_crtc *crtc;
>> +
>> +if (!encoder)
>> +continue;
>> +
>> +encoder_funcs = encoder->helper_private;
>> +if (encoder_funcs && encoder_funcs->mode_valid)
>> +ret = encoder_funcs->mode_valid(encoder, mode);
>> +else
>> +ret = MODE_OK; /* encoder accepts everything */
> Since you already added the drm_bridge_mode_valid() helper, maybe add one
> for connectors, encoders and crtcs as well. Might keep the logic in this
> function a bit more clear on account of not having to check for the
> presence of the vfunc. Right now all three cases look slightly
> different from one another.

Ok, will add in next version. Thanks!

Best regards,
Jose Miguel Abreu

>
>> +
>> +/* No point in continuing for crtc check as this encoder will
>> + * not accept the mode anyway. If all encoders reject the mode
>> + * then, at exit, ret will not be MODE_OK. */
>> +if (ret != MODE_OK)
>> +continue;
>> +
>> +drm_for_each_crtc(crtc, dev) {
>> +const struct drm_crtc_helper_funcs *crtc_funcs;
>> +
>> +if (!drm_encoder_crtc_ok(encoder, crtc))
>> +continue;
>> +
>> +crtc_funcs = crtc->helper_private;
>> +if (!crtc_funcs || !crtc_funcs->mode_valid)
>> +return MODE_OK; /* crtc accepts everything */
>> +
>> +ret = crtc_funcs->mode_valid(crtc, mode);
>> +if (ret == MODE_OK)
>> +/* If we get to this point there is at least
>> + * one combination of encoder+crtc that works
>> + * for this mode. Lets return now. */
>> +return ret;
>> +}
>> +}
>> +
>> +return ret;
>> +}
>> +
>>  static int drm_helper_probe_add_cmdline_mode(struct drm_connector 
>> *connector)
>>  {
>>  struct drm_cmdline_mode *cmdline_mode;
>> @@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
>>   *  (if specified)
>>   *- drm_mode_validate_flag() checks the modes against basic connector
>>   *  capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
>> - *- the optional _connector_helper_funcs.mode_valid helper can 
>> perform
>> - *  driver and/or hardware specific checks
>> + *- the optional _connector_helper_funcs.mode_valid,
>> + *  _crtc_helper_funcs.mode_valid and
>> + *  _encoder_helper_funcs.mode_valid helpers can perform driver 
>> and/or
>> + *  hardware specific checks
>>   *
>>   * 5. Any mode whose status is not OK is pruned from the connector's 

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Ville Syrjälä]

On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
> This changes the connector probe helper function to use the new
> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
> validate the modes.
> 
> The new callbacks are optional so the behaviour remains the same
> if they are not implemented. If they are, then the code loops
> through all the connector's encodersXcrtcs and calls the
> callback.
> 
> If at least a valid encoderXcrtc combination is found which
> accepts the mode then the function returns MODE_OK.
> 
> Signed-off-by: Jose Abreu 
> Cc: Carlos Palminha 
> Cc: Alexey Brodkin 
> Cc: Ville Syrjälä 
> Cc: Daniel Vetter 
> Cc: Dave Airlie 
> Cc: Andrzej Hajda 
> Cc: Archit Taneja 
> ---
>  drivers/gpu/drm/drm_probe_helper.c | 71 
> +++---
>  1 file changed, 67 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> b/drivers/gpu/drm/drm_probe_helper.c
> index 1b0c14a..bf19f82 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -80,6 +80,67 @@
>   return MODE_OK;
>  }
>  
> +static enum drm_mode_status
> +drm_mode_validate_connector(struct drm_connector *connector,
> + struct drm_display_mode *mode)
> +{
> + const struct drm_connector_helper_funcs *connector_funcs =
> + connector->helper_private;
> + struct drm_device *dev = connector->dev;
> + uint32_t *ids = connector->encoder_ids;
> + enum drm_mode_status ret = MODE_OK;
> + unsigned int i;
> +
> + /* Step 1: Validate against connector */
> + if (connector_funcs && connector_funcs->mode_valid)
> + ret = connector_funcs->mode_valid(connector, mode);
> +
> + if (ret != MODE_OK)
> + return ret;
> +
> + /* Step 2: Validate against encoders and crtcs */
> + for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> + struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
> + const struct drm_encoder_helper_funcs *encoder_funcs;
> + struct drm_crtc *crtc;
> +
> + if (!encoder)
> + continue;
> +
> + encoder_funcs = encoder->helper_private;
> + if (encoder_funcs && encoder_funcs->mode_valid)
> + ret = encoder_funcs->mode_valid(encoder, mode);
> + else
> + ret = MODE_OK; /* encoder accepts everything */

Since you already added the drm_bridge_mode_valid() helper, maybe add one
for connectors, encoders and crtcs as well. Might keep the logic in this
function a bit more clear on account of not having to check for the
presence of the vfunc. Right now all three cases look slightly
different from one another.

> +
> + /* No point in continuing for crtc check as this encoder will
> +  * not accept the mode anyway. If all encoders reject the mode
> +  * then, at exit, ret will not be MODE_OK. */
> + if (ret != MODE_OK)
> + continue;
> +
> + drm_for_each_crtc(crtc, dev) {
> + const struct drm_crtc_helper_funcs *crtc_funcs;
> +
> + if (!drm_encoder_crtc_ok(encoder, crtc))
> + continue;
> +
> + crtc_funcs = crtc->helper_private;
> + if (!crtc_funcs || !crtc_funcs->mode_valid)
> + return MODE_OK; /* crtc accepts everything */
> +
> + ret = crtc_funcs->mode_valid(crtc, mode);
> + if (ret == MODE_OK)
> + /* If we get to this point there is at least
> +  * one combination of encoder+crtc that works
> +  * for this mode. Lets return now. */
> + return ret;
> + }
> + }
> +
> + return ret;
> +}
> +
>  static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
>  {
>   struct drm_cmdline_mode *cmdline_mode;
> @@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
>   *  (if specified)
>   *- drm_mode_validate_flag() checks the modes against basic connector
>   *  capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
> - *- the optional _connector_helper_funcs.mode_valid helper can 
> perform
> - *  driver and/or hardware specific checks
> + *- the optional _connector_helper_funcs.mode_valid,
> + *   _crtc_helper_funcs.mode_valid and
> + *   _encoder_helper_funcs.mode_valid helpers can perform driver 
> and/or
> + *   hardware specific checks
>   *
>   * 5. Any mode whose status is not OK is pruned from the connector's modes 
> list,
>   

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

[Ville Syrjälä]

On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
> This changes the connector probe helper function to use the new
> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
> validate the modes.
> 
> The new callbacks are optional so the behaviour remains the same
> if they are not implemented. If they are, then the code loops
> through all the connector's encodersXcrtcs and calls the
> callback.
> 
> If at least a valid encoderXcrtc combination is found which
> accepts the mode then the function returns MODE_OK.
> 
> Signed-off-by: Jose Abreu 
> Cc: Carlos Palminha 
> Cc: Alexey Brodkin 
> Cc: Ville Syrjälä 
> Cc: Daniel Vetter 
> Cc: Dave Airlie 
> Cc: Andrzej Hajda 
> Cc: Archit Taneja 
> ---
>  drivers/gpu/drm/drm_probe_helper.c | 71 
> +++---
>  1 file changed, 67 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> b/drivers/gpu/drm/drm_probe_helper.c
> index 1b0c14a..bf19f82 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -80,6 +80,67 @@
>   return MODE_OK;
>  }
>  
> +static enum drm_mode_status
> +drm_mode_validate_connector(struct drm_connector *connector,
> + struct drm_display_mode *mode)
> +{
> + const struct drm_connector_helper_funcs *connector_funcs =
> + connector->helper_private;
> + struct drm_device *dev = connector->dev;
> + uint32_t *ids = connector->encoder_ids;
> + enum drm_mode_status ret = MODE_OK;
> + unsigned int i;
> +
> + /* Step 1: Validate against connector */
> + if (connector_funcs && connector_funcs->mode_valid)
> + ret = connector_funcs->mode_valid(connector, mode);
> +
> + if (ret != MODE_OK)
> + return ret;
> +
> + /* Step 2: Validate against encoders and crtcs */
> + for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> + struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
> + const struct drm_encoder_helper_funcs *encoder_funcs;
> + struct drm_crtc *crtc;
> +
> + if (!encoder)
> + continue;
> +
> + encoder_funcs = encoder->helper_private;
> + if (encoder_funcs && encoder_funcs->mode_valid)
> + ret = encoder_funcs->mode_valid(encoder, mode);
> + else
> + ret = MODE_OK; /* encoder accepts everything */

Since you already added the drm_bridge_mode_valid() helper, maybe add one
for connectors, encoders and crtcs as well. Might keep the logic in this
function a bit more clear on account of not having to check for the
presence of the vfunc. Right now all three cases look slightly
different from one another.

> +
> + /* No point in continuing for crtc check as this encoder will
> +  * not accept the mode anyway. If all encoders reject the mode
> +  * then, at exit, ret will not be MODE_OK. */
> + if (ret != MODE_OK)
> + continue;
> +
> + drm_for_each_crtc(crtc, dev) {
> + const struct drm_crtc_helper_funcs *crtc_funcs;
> +
> + if (!drm_encoder_crtc_ok(encoder, crtc))
> + continue;
> +
> + crtc_funcs = crtc->helper_private;
> + if (!crtc_funcs || !crtc_funcs->mode_valid)
> + return MODE_OK; /* crtc accepts everything */
> +
> + ret = crtc_funcs->mode_valid(crtc, mode);
> + if (ret == MODE_OK)
> + /* If we get to this point there is at least
> +  * one combination of encoder+crtc that works
> +  * for this mode. Lets return now. */
> + return ret;
> + }
> + }
> +
> + return ret;
> +}
> +
>  static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
>  {
>   struct drm_cmdline_mode *cmdline_mode;
> @@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
>   *  (if specified)
>   *- drm_mode_validate_flag() checks the modes against basic connector
>   *  capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
> - *- the optional _connector_helper_funcs.mode_valid helper can 
> perform
> - *  driver and/or hardware specific checks
> + *- the optional _connector_helper_funcs.mode_valid,
> + *   _crtc_helper_funcs.mode_valid and
> + *   _encoder_helper_funcs.mode_valid helpers can perform driver 
> and/or
> + *   hardware specific checks
>   *
>   * 5. Any mode whose status is not OK is pruned from the connector's modes 
> list,
>   *accompanied by a debug message indicating the reason for the mode's
> @@ -428,8 +491,8 @@ int drm_helper_probe_single_connector_modes(struct 
> drm_connector *connector,
>