[PATCH] i915/fbc: Disable on HSW by default for now

[PATCH] i915/fbc: Disable on HSW by default for now

[Lyude]

>From https://bugs.freedesktop.org/show_bug.cgi?id=96461 :

This was kind of a difficult bug to track down. If you're using a
Haswell system running GNOME and you have fbc completely enabled and
working, playing videos can result in video artifacts. Steps to
reproduce:

- Run GNOME
- Ensure FBC is enabled and active
- Download a movie, I used the ogg version of Big Buck Bunny for this
- Run `gst-launch-1.0 filesrc location='some_movie.ogg' ! decodebin !
  glimagesink` in a terminal
- Watch for about over a minute, you'll see small horizontal lines go
  down the screen.

For the time being, disable FBC for Haswell by default.

Signed-off-by: Lyude <cpaul@redhat.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/i915/intel_fbc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index 0f0492f..28f4407 100644
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -823,8 +823,7 @@ static bool intel_fbc_can_choose(struct intel_crtc *crtc)
 {
 	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
 	struct intel_fbc *fbc = &dev_priv->fbc;
-	bool enable_by_default = IS_HASWELL(dev_priv) ||
-				 IS_BROADWELL(dev_priv);
+	bool enable_by_default = IS_BROADWELL(dev_priv);
 
 	if (intel_vgpu_active(dev_priv->dev)) {
 		fbc->no_fbc_reason = "VGPU is active";
-- 
2.5.5

Re: [PATCH] i915/fbc: Disable on HSW by default for now

[Zanoni, Paulo R]

Em Qui, 2016-06-09 às 11:58 -0400, Lyude escreveu:
> From https://bugs.freedesktop.org/show_bug.cgi?id=96461 :
> 
> This was kind of a difficult bug to track down. If you're using a
> Haswell system running GNOME and you have fbc completely enabled and
> working, playing videos can result in video artifacts. Steps to
> reproduce:
> 
> - Run GNOME
> - Ensure FBC is enabled and active
> - Download a movie, I used the ogg version of Big Buck Bunny for this
> - Run `gst-launch-1.0 filesrc location='some_movie.ogg' ! decodebin !
>   glimagesink` in a terminal
> - Watch for about over a minute, you'll see small horizontal lines go
>   down the screen.

If you "dmesg | grep -i underrun", do you see anything (even if it
doesn't happen during the moments of corruption)?

Does the problem still happen if you apply these patches?
 - https://patchwork.freedesktop.org/patch/79567/
 - https://patchwork.freedesktop.org/patch/80857/
 - https://patchwork.freedesktop.org/patch/92634/

> 
> For the time being, disable FBC for Haswell by default.

In case we want to improve the commit message:

We also got reports from Steven Honeyman on openbox+roxterm, and from
Stefan Richter.

Anyway, there's a regression that needs to be fixed, so:

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

We can always try again later.

> 
> Signed-off-by: Lyude <cpaul@redhat.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/gpu/drm/i915/intel_fbc.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_fbc.c
> b/drivers/gpu/drm/i915/intel_fbc.c
> index 0f0492f..28f4407 100644
> --- a/drivers/gpu/drm/i915/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/intel_fbc.c
> @@ -823,8 +823,7 @@ static bool intel_fbc_can_choose(struct
> intel_crtc *crtc)
>  {
>  	struct drm_i915_private *dev_priv = crtc->base.dev-
> >dev_private;
>  	struct intel_fbc *fbc = &dev_priv->fbc;
> -	bool enable_by_default = IS_HASWELL(dev_priv) ||
> -				 IS_BROADWELL(dev_priv);
> +	bool enable_by_default = IS_BROADWELL(dev_priv);
>  
>  	if (intel_vgpu_active(dev_priv->dev)) {
>  		fbc->no_fbc_reason = "VGPU is active";

Re: [PATCH] i915/fbc: Disable on HSW by default for now

[Stefan Richter]

On Jun 09 Zanoni, Paulo R wrote:
> Em Qui, 2016-06-09 às 11:58 -0400, Lyude escreveu:
> > From https://bugs.freedesktop.org/show_bug.cgi?id=96461 :
> > 
> > This was kind of a difficult bug to track down. If you're using a
> > Haswell system running GNOME and you have fbc completely enabled and
> > working, playing videos can result in video artifacts.
[...]
> > For the time being, disable FBC for Haswell by default.  
> 
> In case we want to improve the commit message:
> 
> We also got reports from Steven Honeyman on openbox+roxterm, and from
> Stefan Richter.

Perhaps also worth mentioning in the changelog:
Stefan Richter reported kernel freezes (no video artifacts) when fbc is on.
(E3-1245 v3 with HD P4600; openbox and some KDE and LXDE applications,
thread begins at https://lkml.org/lkml/2016/4/26/813)
-- 
Stefan Richter
-======----- -==- -=-=-
http://arcgraph.de/sr/

Re: [PATCH] i915/fbc: Disable on HSW by default for now

[Zanoni, Paulo R]

Em Sex, 2016-06-10 às 08:44 +0200, Stefan Richter escreveu:
> On Jun 09 Zanoni, Paulo R wrote:
> > 
> > Em Qui, 2016-06-09 às 11:58 -0400, Lyude escreveu:
> > > 
> > > From https://bugs.freedesktop.org/show_bug.cgi?id=96461 :
> > > 
> > > This was kind of a difficult bug to track down. If you're using a
> > > Haswell system running GNOME and you have fbc completely enabled
> > > and
> > > working, playing videos can result in video artifacts.
> [...]
> > 
> > > 
> > > For the time being, disable FBC for Haswell by default.  
> > In case we want to improve the commit message:
> > 
> > We also got reports from Steven Honeyman on openbox+roxterm, and
> > from
> > Stefan Richter.
> Perhaps also worth mentioning in the changelog:
> Stefan Richter reported kernel freezes (no video artifacts) when fbc
> is on.
> (E3-1245 v3 with HD P4600; openbox and some KDE and LXDE
> applications,
> thread begins at https://lkml.org/lkml/2016/4/26/813)

Patch merged with small additions to the commit message.

Thanks everybody involved,
Paulo