Re: [Intel-gfx] [PATCH] drm/i915/display: Add missing checks for cdclk crawling
> -Original Message-
> From: Ville Syrjälä
> Sent: Friday, November 11, 2022 11:40 AM
> To: Srivatsa, Anusha
> Cc: intel-gfx@lists.freedesktop.org; Roper, Matthew D
>
> Subject: Re: [PATCH] drm/i915/display: Add missing checks for cdclk crawling
>
> On Fri, Nov 11, 2022 at 11:26:02AM -0800, Anusha Srivatsa wrote:
> > cdclk_sanitize() function was written assuming vco was a signed integer.
> > vco gets assigned to -1 (essentially ~0) for the case where PLL might
> > be enabled and vco is not a frequency that will ever get used. In such
> > a scenario the right thing to do is disable the PLL and re-enable it
> > again with a valid frequency.
> > However the vco is declared as a unsigned variable.
> > With the above assumption, driver takes crawl path when not needed.
> > Add explicit check to not crawl in the case of an invalid PLL.
> >
> > v2: Move the check from .h to .c (MattR)
> > - Move check to bxt_set_cdclk() instead of
> > intel_modeset_calc_cdclk() which is directly in the path of the
> > sanitize() function (Ville)
> >
> > Cc: Ville Syrjälä
> > Cc: Matt Roper
> > Suggested-by: Ville Syrjälä
> > Signed-off-by: Anusha Srivatsa
> > ---
> > drivers/gpu/drm/i915/display/intel_cdclk.c | 13 -
> > 1 file changed, 12 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c
> > b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > index 8a9031012d74..2d9b7ba58358 100644
> > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > @@ -1716,6 +1716,16 @@ static void dg2_cdclk_squash_program(struct
> drm_i915_private *i915,
> > intel_de_write(i915, CDCLK_SQUASH_CTL, squash_ctl); }
> >
> > +static bool cdclk_pll_is_unknown(unsigned int vco) {
> > + /*
> > +* Ensure driver does not take the crawl path for the
> > +* case when the vco is set to ~0 in the
> > +* sanitize path.
> > +*/
> > + return (vco == ~0);
>
> Pointless parens.
>
> > +}
> > +
> > static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
> > const struct intel_cdclk_config *cdclk_config,
> > enum pipe pipe)
> > @@ -1748,7 +1758,8 @@ static void bxt_set_cdclk(struct drm_i915_private
> *dev_priv,
> > return;
> > }
> >
> > - if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco
> > 0 && vco > 0) {
> > + if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco
> > 0 && vco > 0 &&
> > + (!cdclk_pll_is_unknown(dev_priv->display.cdclk.hw.vco))) {
>
> More pointless parens
>
> With those removed
> Reviewed-by: Ville Syrjälä
Thanks Ville.
> Though I think we should probably add the pll_is_enabled() helper too, just
> make the code a bit more self explanatory.
At this point the current code should atleast not block the MTL cdclk churn
series. But the suggested helper will make the code more explanatory and I can
take it up.
Thanks for the feedback!
Anusha
> > if (dev_priv->display.cdclk.hw.vco != vco)
> > adlp_cdclk_pll_crawl(dev_priv, vco);
> > } else if (DISPLAY_VER(dev_priv) >= 11)
> > --
> > 2.25.1
>
> --
> Ville Syrjälä
> Intel
Re: [Intel-gfx] [PATCH] drm/i915/display: Add missing checks for cdclk crawling
On Fri, Nov 11, 2022 at 11:26:02AM -0800, Anusha Srivatsa wrote:
> cdclk_sanitize() function was written assuming vco was a signed integer.
> vco gets assigned to -1 (essentially ~0) for the case where PLL
> might be enabled and vco is not a frequency that will ever
> get used. In such a scenario the right thing to do is disable the
> PLL and re-enable it again with a valid frequency.
> However the vco is declared as a unsigned variable.
> With the above assumption, driver takes crawl path when not needed.
> Add explicit check to not crawl in the case of an invalid PLL.
>
> v2: Move the check from .h to .c (MattR)
> - Move check to bxt_set_cdclk() instead of
> intel_modeset_calc_cdclk() which is directly in
> the path of the sanitize() function (Ville)
>
> Cc: Ville Syrjälä
> Cc: Matt Roper
> Suggested-by: Ville Syrjälä
> Signed-off-by: Anusha Srivatsa
> ---
> drivers/gpu/drm/i915/display/intel_cdclk.c | 13 -
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c
> b/drivers/gpu/drm/i915/display/intel_cdclk.c
> index 8a9031012d74..2d9b7ba58358 100644
> --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> @@ -1716,6 +1716,16 @@ static void dg2_cdclk_squash_program(struct
> drm_i915_private *i915,
> intel_de_write(i915, CDCLK_SQUASH_CTL, squash_ctl);
> }
>
> +static bool cdclk_pll_is_unknown(unsigned int vco)
> +{
> + /*
> + * Ensure driver does not take the crawl path for the
> + * case when the vco is set to ~0 in the
> + * sanitize path.
> + */
> + return (vco == ~0);
Pointless parens.
> +}
> +
> static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
> const struct intel_cdclk_config *cdclk_config,
> enum pipe pipe)
> @@ -1748,7 +1758,8 @@ static void bxt_set_cdclk(struct drm_i915_private
> *dev_priv,
> return;
> }
>
> - if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 &&
> vco > 0) {
> + if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 &&
> vco > 0 &&
> + (!cdclk_pll_is_unknown(dev_priv->display.cdclk.hw.vco))) {
More pointless parens
With those removed
Reviewed-by: Ville Syrjälä
Though I think we should probably add the pll_is_enabled()
helper too, just make the code a bit more self explanatory.
> if (dev_priv->display.cdclk.hw.vco != vco)
> adlp_cdclk_pll_crawl(dev_priv, vco);
> } else if (DISPLAY_VER(dev_priv) >= 11)
> --
> 2.25.1
--
Ville Syrjälä
Intel
[Intel-gfx] [PATCH] drm/i915/display: Add missing checks for cdclk crawling
cdclk_sanitize() function was written assuming vco was a signed integer.
vco gets assigned to -1 (essentially ~0) for the case where PLL
might be enabled and vco is not a frequency that will ever
get used. In such a scenario the right thing to do is disable the
PLL and re-enable it again with a valid frequency.
However the vco is declared as a unsigned variable.
With the above assumption, driver takes crawl path when not needed.
Add explicit check to not crawl in the case of an invalid PLL.
v2: Move the check from .h to .c (MattR)
- Move check to bxt_set_cdclk() instead of
intel_modeset_calc_cdclk() which is directly in
the path of the sanitize() function (Ville)
Cc: Ville Syrjälä
Cc: Matt Roper
Suggested-by: Ville Syrjälä
Signed-off-by: Anusha Srivatsa
---
drivers/gpu/drm/i915/display/intel_cdclk.c | 13 -
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c
b/drivers/gpu/drm/i915/display/intel_cdclk.c
index 8a9031012d74..2d9b7ba58358 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -1716,6 +1716,16 @@ static void dg2_cdclk_squash_program(struct
drm_i915_private *i915,
intel_de_write(i915, CDCLK_SQUASH_CTL, squash_ctl);
}
+static bool cdclk_pll_is_unknown(unsigned int vco)
+{
+ /*
+* Ensure driver does not take the crawl path for the
+* case when the vco is set to ~0 in the
+* sanitize path.
+*/
+ return (vco == ~0);
+}
+
static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
const struct intel_cdclk_config *cdclk_config,
enum pipe pipe)
@@ -1748,7 +1758,8 @@ static void bxt_set_cdclk(struct drm_i915_private
*dev_priv,
return;
}
- if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 &&
vco > 0) {
+ if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 &&
vco > 0 &&
+ (!cdclk_pll_is_unknown(dev_priv->display.cdclk.hw.vco))) {
if (dev_priv->display.cdclk.hw.vco != vco)
adlp_cdclk_pll_crawl(dev_priv, vco);
} else if (DISPLAY_VER(dev_priv) >= 11)
--
2.25.1
Re: [Intel-gfx] [PATCH] drm/i915/display: Add missing checks for cdclk crawling
On Wed, Nov 09, 2022 at 09:37:24PM -0800, Anusha Srivatsa wrote: > cdclk_sanitize() function was written assuming vco was a signed integer. > vco gets assigned to -1 (essentially ~0) for the case where PLL > might be enabled and vco is not a frequency that will ever > get used. In such a scenario the right thing to do is disable the > PLL and re-enable it again with a valid frequency. > However the vco is declared as a unsigned variable. > With the above assumption, driver takes crawl path when not needed. > Add explicit check to not crawl in the case of an invalid PLL. > > Cc: Matt Roper > Suggested-by: Ville Syrjälä > Signed-off-by: Anusha Srivatsa > --- > drivers/gpu/drm/i915/display/intel_cdclk.c | 2 ++ > drivers/gpu/drm/i915/display/intel_cdclk.h | 1 + > 2 files changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c > b/drivers/gpu/drm/i915/display/intel_cdclk.c > index 8a9031012d74..91112d266763 100644 > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c > @@ -1962,6 +1962,8 @@ static bool intel_cdclk_can_crawl(struct > drm_i915_private *dev_priv, > if (!HAS_CDCLK_CRAWL(dev_priv)) > return false; > > + if (intel_pll_is_unknown(a->vco)) > + return false; I think this guy is only called from the atomic_check() path, so this check shouldn't be needed here. Where we do need it is the crawl check bxt_set_cdclk() since that is what gets called directly from the sanitize() path with hw.vco=~0. > /* >* The vco and cd2x divider will change independently >* from each, so we disallow cd2x change when crawling. > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.h > b/drivers/gpu/drm/i915/display/intel_cdclk.h > index c674879a84a5..6eb83d806f11 100644 > --- a/drivers/gpu/drm/i915/display/intel_cdclk.h > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.h > @@ -80,6 +80,7 @@ intel_atomic_get_cdclk_state(struct intel_atomic_state > *state); > to_intel_cdclk_state(intel_atomic_get_old_global_obj_state(state, > _i915(state->base.dev)->display.cdclk.obj)) > #define intel_atomic_get_new_cdclk_state(state) \ > to_intel_cdclk_state(intel_atomic_get_new_global_obj_state(state, > _i915(state->base.dev)->display.cdclk.obj)) > +#define intel_pll_is_unknown(vco)((vco) == ~0) > > int intel_cdclk_init(struct drm_i915_private *dev_priv); > > -- > 2.25.1 -- Ville Syrjälä Intel
Re: [Intel-gfx] [PATCH] drm/i915/display: Add missing checks for cdclk crawling
On Thu, Nov 10, 2022 at 01:28:19PM +0200, Jani Nikula wrote:
> On Wed, 09 Nov 2022, Anusha Srivatsa wrote:
> > cdclk_sanitize() function was written assuming vco was a signed integer.
> > vco gets assigned to -1 (essentially ~0) for the case where PLL
> > might be enabled and vco is not a frequency that will ever
> > get used. In such a scenario the right thing to do is disable the
> > PLL and re-enable it again with a valid frequency.
> > However the vco is declared as a unsigned variable.
> > With the above assumption, driver takes crawl path when not needed.
> > Add explicit check to not crawl in the case of an invalid PLL.
> >
> > Cc: Matt Roper
> > Suggested-by: Ville Syrjälä
> > Signed-off-by: Anusha Srivatsa
> > ---
> > drivers/gpu/drm/i915/display/intel_cdclk.c | 2 ++
> > drivers/gpu/drm/i915/display/intel_cdclk.h | 1 +
> > 2 files changed, 3 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c
> > b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > index 8a9031012d74..91112d266763 100644
> > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > @@ -1962,6 +1962,8 @@ static bool intel_cdclk_can_crawl(struct
> > drm_i915_private *dev_priv,
> > if (!HAS_CDCLK_CRAWL(dev_priv))
> > return false;
> >
> > + if (intel_pll_is_unknown(a->vco))
> > + return false;
> > /*
> > * The vco and cd2x divider will change independently
> > * from each, so we disallow cd2x change when crawling.
> > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.h
> > b/drivers/gpu/drm/i915/display/intel_cdclk.h
> > index c674879a84a5..6eb83d806f11 100644
> > --- a/drivers/gpu/drm/i915/display/intel_cdclk.h
> > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.h
> > @@ -80,6 +80,7 @@ intel_atomic_get_cdclk_state(struct intel_atomic_state
> > *state);
> > to_intel_cdclk_state(intel_atomic_get_old_global_obj_state(state,
> > _i915(state->base.dev)->display.cdclk.obj))
> > #define intel_atomic_get_new_cdclk_state(state) \
> > to_intel_cdclk_state(intel_atomic_get_new_global_obj_state(state,
> > _i915(state->base.dev)->display.cdclk.obj))
> > +#define intel_pll_is_unknown(vco) ((vco) == ~0)
>
> Why here? What does a pll function do in intel_cdclk.h?
Since this is referring to the cdclk pll (not port pll's), I suspect
this shouldn't be needed anywhere outside the cdclk code. So it might
be best just make this a static function inside the cdclk .c file rather
than placing it in a header that exposes it to the rest of the driver.
I.e., something like:
static bool pll_us_unknown(struct intel_cdclk_state *s) {
return (s->vco == ~0);
}
Matt
>
> BR,
> Jani.
>
> >
> > int intel_cdclk_init(struct drm_i915_private *dev_priv);
>
> --
> Jani Nikula, Intel Open Source Graphics Center
--
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
Re: [Intel-gfx] [PATCH] drm/i915/display: Add missing checks for cdclk crawling
On Wed, 09 Nov 2022, Anusha Srivatsa wrote: > cdclk_sanitize() function was written assuming vco was a signed integer. > vco gets assigned to -1 (essentially ~0) for the case where PLL > might be enabled and vco is not a frequency that will ever > get used. In such a scenario the right thing to do is disable the > PLL and re-enable it again with a valid frequency. > However the vco is declared as a unsigned variable. > With the above assumption, driver takes crawl path when not needed. > Add explicit check to not crawl in the case of an invalid PLL. > > Cc: Matt Roper > Suggested-by: Ville Syrjälä > Signed-off-by: Anusha Srivatsa > --- > drivers/gpu/drm/i915/display/intel_cdclk.c | 2 ++ > drivers/gpu/drm/i915/display/intel_cdclk.h | 1 + > 2 files changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c > b/drivers/gpu/drm/i915/display/intel_cdclk.c > index 8a9031012d74..91112d266763 100644 > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c > @@ -1962,6 +1962,8 @@ static bool intel_cdclk_can_crawl(struct > drm_i915_private *dev_priv, > if (!HAS_CDCLK_CRAWL(dev_priv)) > return false; > > + if (intel_pll_is_unknown(a->vco)) > + return false; > /* >* The vco and cd2x divider will change independently >* from each, so we disallow cd2x change when crawling. > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.h > b/drivers/gpu/drm/i915/display/intel_cdclk.h > index c674879a84a5..6eb83d806f11 100644 > --- a/drivers/gpu/drm/i915/display/intel_cdclk.h > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.h > @@ -80,6 +80,7 @@ intel_atomic_get_cdclk_state(struct intel_atomic_state > *state); > to_intel_cdclk_state(intel_atomic_get_old_global_obj_state(state, > _i915(state->base.dev)->display.cdclk.obj)) > #define intel_atomic_get_new_cdclk_state(state) \ > to_intel_cdclk_state(intel_atomic_get_new_global_obj_state(state, > _i915(state->base.dev)->display.cdclk.obj)) > +#define intel_pll_is_unknown(vco)((vco) == ~0) Why here? What does a pll function do in intel_cdclk.h? BR, Jani. > > int intel_cdclk_init(struct drm_i915_private *dev_priv); -- Jani Nikula, Intel Open Source Graphics Center
[Intel-gfx] [PATCH] drm/i915/display: Add missing checks for cdclk crawling
cdclk_sanitize() function was written assuming vco was a signed integer. vco gets assigned to -1 (essentially ~0) for the case where PLL might be enabled and vco is not a frequency that will ever get used. In such a scenario the right thing to do is disable the PLL and re-enable it again with a valid frequency. However the vco is declared as a unsigned variable. With the above assumption, driver takes crawl path when not needed. Add explicit check to not crawl in the case of an invalid PLL. Cc: Matt Roper Suggested-by: Ville Syrjälä Signed-off-by: Anusha Srivatsa --- drivers/gpu/drm/i915/display/intel_cdclk.c | 2 ++ drivers/gpu/drm/i915/display/intel_cdclk.h | 1 + 2 files changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c index 8a9031012d74..91112d266763 100644 --- a/drivers/gpu/drm/i915/display/intel_cdclk.c +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c @@ -1962,6 +1962,8 @@ static bool intel_cdclk_can_crawl(struct drm_i915_private *dev_priv, if (!HAS_CDCLK_CRAWL(dev_priv)) return false; + if (intel_pll_is_unknown(a->vco)) + return false; /* * The vco and cd2x divider will change independently * from each, so we disallow cd2x change when crawling. diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.h b/drivers/gpu/drm/i915/display/intel_cdclk.h index c674879a84a5..6eb83d806f11 100644 --- a/drivers/gpu/drm/i915/display/intel_cdclk.h +++ b/drivers/gpu/drm/i915/display/intel_cdclk.h @@ -80,6 +80,7 @@ intel_atomic_get_cdclk_state(struct intel_atomic_state *state); to_intel_cdclk_state(intel_atomic_get_old_global_obj_state(state, _i915(state->base.dev)->display.cdclk.obj)) #define intel_atomic_get_new_cdclk_state(state) \ to_intel_cdclk_state(intel_atomic_get_new_global_obj_state(state, _i915(state->base.dev)->display.cdclk.obj)) +#define intel_pll_is_unknown(vco) ((vco) == ~0) int intel_cdclk_init(struct drm_i915_private *dev_priv); -- 2.25.1
