Re: [Intel-gfx] [PATCH v4 05/11] drm: Helper to read max bits per component

2016-06-09 Thread Mika Kahola 
On Thu, 2016-06-09 at 11:02 +0300, Ville Syrjälä wrote:
> On Mon, Jun 06, 2016 at 04:29:07PM +0300, Mika Kahola wrote:
> > Helper routine to read out maximum supported bits per
> > component for DisplayPort legay converters.
> > 
> > Signed-off-by: Mika Kahola 
> > ---
> >  drivers/gpu/drm/drm_dp_helper.c | 31 +++
> >  include/drm/drm_dp_helper.h |  2 ++
> >  2 files changed, 33 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_dp_helper.c 
> > b/drivers/gpu/drm/drm_dp_helper.c
> > index 18b72eb..bac0ccc 100644
> > --- a/drivers/gpu/drm/drm_dp_helper.c
> > +++ b/drivers/gpu/drm/drm_dp_helper.c
> > @@ -507,6 +507,37 @@ int drm_dp_downstream_max_clock(const u8 
> > dpcd[DP_RECEIVER_CAP_SIZE],
> >  }
> >  EXPORT_SYMBOL(drm_dp_downstream_max_clock);
> >  
> > +/**
> > + * drm_dp_downstream_max_bpc() - extract branch device max
> > + *   bits per component
> > + * @dpcd: DisplayPort configuration data
> > + * @port_cap: port capabilities
> > + *
> > + * Returns max bpc on success or negative error code on failure
> > + */
> > +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> > +  const u8 port_cap[4])
> > +{
> > +   int type = drm_dp_downstream_type(dpcd, port_cap);
> > +   bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> > +   DP_DETAILED_CAP_INFO_AVAILABLE;
> > +
> > +   if (detailed_cap_info) {
> 
> Early return again.
> 
> > +   if (type != DP_DS_PORT_TYPE_WIRELESS) {
> 
> switch() again.
> 
> > +   int tmp;
> > +   tmp = port_cap[2] & DP_DS_VGA_MAX_BPC_MASK;
> 
> Should drop the "VGA" from that stuff since it applies to more than
> that.

Agreed. Maybe we could rename it as DP_DS_MAX_BPC_MASK instead.

> 
> > +
> > +   if (tmp == 0)
> > +   return 8;
> > +   else
> > +   return 8 + (1< 
> switch() with each case would be less magicy.
> 
> > +   }
> > +   }
> > +
> > +   return -EINVAL;
> 
> Again I think I'd just use 0 here.
> 
> > +}
> > +EXPORT_SYMBOL(drm_dp_downstream_max_bpc);
> > +
> >  /*
> >   * I2C-over-AUX implementation
> >   */
> > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> > index c3324d3..d4abc38 100644
> > --- a/include/drm/drm_dp_helper.h
> > +++ b/include/drm/drm_dp_helper.h
> > @@ -812,6 +812,8 @@ int drm_dp_downstream_port_cap(struct drm_dp_aux *aux,
> >  int drm_dp_downstream_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 
> > port_cap[4]);
> >  int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> >  const u8 port_cap[4]);
> > +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> > +  const u8 port_cap[4]);
> >  
> >  int drm_dp_aux_register(struct drm_dp_aux *aux);
> >  void drm_dp_aux_unregister(struct drm_dp_aux *aux);
> > -- 
> > 1.9.1
> 

-- 
Mika Kahola - Intel OTC

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Re: [Intel-gfx] [PATCH v4 05/11] drm: Helper to read max bits per component

2016-06-09 Thread Ville Syrjälä 
On Mon, Jun 06, 2016 at 04:29:07PM +0300, Mika Kahola wrote:
> Helper routine to read out maximum supported bits per
> component for DisplayPort legay converters.
> 
> Signed-off-by: Mika Kahola 
> ---
>  drivers/gpu/drm/drm_dp_helper.c | 31 +++
>  include/drm/drm_dp_helper.h |  2 ++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index 18b72eb..bac0ccc 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -507,6 +507,37 @@ int drm_dp_downstream_max_clock(const u8 
> dpcd[DP_RECEIVER_CAP_SIZE],
>  }
>  EXPORT_SYMBOL(drm_dp_downstream_max_clock);
>  
> +/**
> + * drm_dp_downstream_max_bpc() - extract branch device max
> + *   bits per component
> + * @dpcd: DisplayPort configuration data
> + * @port_cap: port capabilities
> + *
> + * Returns max bpc on success or negative error code on failure
> + */
> +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> +  const u8 port_cap[4])
> +{
> + int type = drm_dp_downstream_type(dpcd, port_cap);
> + bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> + DP_DETAILED_CAP_INFO_AVAILABLE;
> +
> + if (detailed_cap_info) {

Early return again.

> + if (type != DP_DS_PORT_TYPE_WIRELESS) {

switch() again.

> + int tmp;
> + tmp = port_cap[2] & DP_DS_VGA_MAX_BPC_MASK;

Should drop the "VGA" from that stuff since it applies to more than
that.

> +
> + if (tmp == 0)
> + return 8;
> + else
> + return 8 + (1< + }
> + }
> +
> + return -EINVAL;

Again I think I'd just use 0 here.

> +}
> +EXPORT_SYMBOL(drm_dp_downstream_max_bpc);
> +
>  /*
>   * I2C-over-AUX implementation
>   */
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index c3324d3..d4abc38 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -812,6 +812,8 @@ int drm_dp_downstream_port_cap(struct drm_dp_aux *aux,
>  int drm_dp_downstream_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 
> port_cap[4]);
>  int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
>  const u8 port_cap[4]);
> +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> +  const u8 port_cap[4]);
>  
>  int drm_dp_aux_register(struct drm_dp_aux *aux);
>  void drm_dp_aux_unregister(struct drm_dp_aux *aux);
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC
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[Intel-gfx] [PATCH v4 05/11] drm: Helper to read max bits per component

2016-06-06 Thread Mika Kahola 
Helper routine to read out maximum supported bits per
component for DisplayPort legay converters.

Signed-off-by: Mika Kahola 
---
 drivers/gpu/drm/drm_dp_helper.c | 31 +++
 include/drm/drm_dp_helper.h |  2 ++
 2 files changed, 33 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 18b72eb..bac0ccc 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -507,6 +507,37 @@ int drm_dp_downstream_max_clock(const u8 
dpcd[DP_RECEIVER_CAP_SIZE],
 }
 EXPORT_SYMBOL(drm_dp_downstream_max_clock);
 
+/**
+ * drm_dp_downstream_max_bpc() - extract branch device max
+ *   bits per component
+ * @dpcd: DisplayPort configuration data
+ * @port_cap: port capabilities
+ *
+ * Returns max bpc on success or negative error code on failure
+ */
+int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+  const u8 port_cap[4])
+{
+   int type = drm_dp_downstream_type(dpcd, port_cap);
+   bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] &
+   DP_DETAILED_CAP_INFO_AVAILABLE;
+
+   if (detailed_cap_info) {
+   if (type != DP_DS_PORT_TYPE_WIRELESS) {
+   int tmp;
+   tmp = port_cap[2] & DP_DS_VGA_MAX_BPC_MASK;
+
+   if (tmp == 0)
+   return 8;
+   else
+   return 8 + (1<