* [PATCH] drm/i915: fix FDI_RX_CHICKEN register read masking
@ 2012-10-29 17:26 Jani Nikula
2012-10-29 17:49 ` Lespiau, Damien
2012-10-29 20:52 ` Daniel Vetter
0 siblings, 2 replies; 4+ messages in thread
From: Jani Nikula @ 2012-10-29 17:26 UTC (permalink / raw)
To: intel-gfx, daniel; +Cc: jani.nikula
Mask the value, not the register. Spotted while reading the code.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
Only compile tested. Is there a bug that might match this?
---
drivers/gpu/drm/i915/intel_display.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a5be346..6f8cf2a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2804,8 +2804,8 @@ static void ironlake_fdi_disable(struct drm_crtc *crtc)
if (HAS_PCH_IBX(dev)) {
I915_WRITE(FDI_RX_CHICKEN(pipe), FDI_RX_PHASE_SYNC_POINTER_OVR);
I915_WRITE(FDI_RX_CHICKEN(pipe),
- I915_READ(FDI_RX_CHICKEN(pipe) &
- ~FDI_RX_PHASE_SYNC_POINTER_EN));
+ I915_READ(FDI_RX_CHICKEN(pipe)) &
+ ~FDI_RX_PHASE_SYNC_POINTER_EN);
} else if (HAS_PCH_CPT(dev)) {
cpt_phase_pointer_disable(dev, pipe);
}
--
1.7.9.5
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] drm/i915: fix FDI_RX_CHICKEN register read masking
2012-10-29 17:26 [PATCH] drm/i915: fix FDI_RX_CHICKEN register read masking Jani Nikula
@ 2012-10-29 17:49 ` Lespiau, Damien
2012-10-29 20:27 ` Daniel Vetter
2012-10-29 20:52 ` Daniel Vetter
1 sibling, 1 reply; 4+ messages in thread
From: Lespiau, Damien @ 2012-10-29 17:49 UTC (permalink / raw)
To: Jani Nikula; +Cc: intel-gfx
On Mon, Oct 29, 2012 at 5:26 PM, Jani Nikula <jani.nikula@intel.com> wrote:
> Mask the value, not the register. Spotted while reading the code.
>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Good catch! FWIW, I ran:
git grep -e "READ.*\(pipe\|plane\|cpu_transcoder\))[^)]*[|&]"
drivers/gpu/drm/i915/
and this was the only catch.
--
Damien
> ---
>
> Only compile tested. Is there a bug that might match this?
> ---
> drivers/gpu/drm/i915/intel_display.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index a5be346..6f8cf2a 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -2804,8 +2804,8 @@ static void ironlake_fdi_disable(struct drm_crtc *crtc)
> if (HAS_PCH_IBX(dev)) {
> I915_WRITE(FDI_RX_CHICKEN(pipe), FDI_RX_PHASE_SYNC_POINTER_OVR);
> I915_WRITE(FDI_RX_CHICKEN(pipe),
> - I915_READ(FDI_RX_CHICKEN(pipe) &
> - ~FDI_RX_PHASE_SYNC_POINTER_EN));
> + I915_READ(FDI_RX_CHICKEN(pipe)) &
> + ~FDI_RX_PHASE_SYNC_POINTER_EN);
> } else if (HAS_PCH_CPT(dev)) {
> cpt_phase_pointer_disable(dev, pipe);
> }
> --
> 1.7.9.5
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] drm/i915: fix FDI_RX_CHICKEN register read masking
2012-10-29 17:49 ` Lespiau, Damien
@ 2012-10-29 20:27 ` Daniel Vetter
0 siblings, 0 replies; 4+ messages in thread
From: Daniel Vetter @ 2012-10-29 20:27 UTC (permalink / raw)
To: Lespiau, Damien; +Cc: Jani Nikula, intel-gfx
On Mon, Oct 29, 2012 at 05:49:48PM +0000, Lespiau, Damien wrote:
> On Mon, Oct 29, 2012 at 5:26 PM, Jani Nikula <jani.nikula@intel.com> wrote:
> > Mask the value, not the register. Spotted while reading the code.
> >
> > Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>
> Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Queued for -next, thanks for the patch.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] drm/i915: fix FDI_RX_CHICKEN register read masking
2012-10-29 17:26 [PATCH] drm/i915: fix FDI_RX_CHICKEN register read masking Jani Nikula
2012-10-29 17:49 ` Lespiau, Damien
@ 2012-10-29 20:52 ` Daniel Vetter
1 sibling, 0 replies; 4+ messages in thread
From: Daniel Vetter @ 2012-10-29 20:52 UTC (permalink / raw)
To: Jani Nikula; +Cc: intel-gfx
On Mon, Oct 29, 2012 at 07:26:42PM +0200, Jani Nikula wrote:
> Mask the value, not the register. Spotted while reading the code.
>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>
> ---
>
> Only compile tested. Is there a bug that might match this?
> ---
> drivers/gpu/drm/i915/intel_display.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index a5be346..6f8cf2a 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -2804,8 +2804,8 @@ static void ironlake_fdi_disable(struct drm_crtc *crtc)
> if (HAS_PCH_IBX(dev)) {
> I915_WRITE(FDI_RX_CHICKEN(pipe), FDI_RX_PHASE_SYNC_POINTER_OVR);
> I915_WRITE(FDI_RX_CHICKEN(pipe),
> - I915_READ(FDI_RX_CHICKEN(pipe) &
> - ~FDI_RX_PHASE_SYNC_POINTER_EN));
> + I915_READ(FDI_RX_CHICKEN(pipe)) &
> + ~FDI_RX_PHASE_SYNC_POINTER_EN);
On second look, we write the same register in the previous line, and the
w/a seems to be to set FDI_RX_PHASE_SYNC_POINTER_OVR to enable the logic,
then keep always set FDI_RX_PHASE_SYNC_POINTER_OVR and toggle
~FDI_RX_PHASE_SYNC_POINTER_EN before/after enabling the pc transcoder. So
the right things seems to be to simply kill the 2nd write.
-Daniel
> } else if (HAS_PCH_CPT(dev)) {
> cpt_phase_pointer_disable(dev, pipe);
> }
> --
> 1.7.9.5
>
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-10-29 20:51 UTC | newest]
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2012-10-29 17:26 [PATCH] drm/i915: fix FDI_RX_CHICKEN register read masking Jani Nikula
2012-10-29 17:49 ` Lespiau, Damien
2012-10-29 20:27 ` Daniel Vetter
2012-10-29 20:52 ` Daniel Vetter
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