[PATCH] drm/i915:: Disable FBC on SandyBridge

[PATCH] drm/i915:: Disable FBC on SandyBridge

[Chris Wilson]

Enabling FBC is causing the BLT ring to run between 10-100x slower than
normal and frequently lockup. The interim solution is disable FBC once
more until we know why.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_display.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 9fa342e..f972a09 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1864,7 +1864,7 @@ static void intel_update_fbc(struct drm_device *dev)
 	if (enable_fbc < 0) {
 		DRM_DEBUG_KMS("fbc set to per-chip default\n");
 		enable_fbc = 1;
-		if (INTEL_INFO(dev)->gen <= 5)
+		if (INTEL_INFO(dev)->gen <= 6)
 			enable_fbc = 0;
 	}
 	if (!enable_fbc) {
-- 
1.7.7.2

Re: [PATCH] drm/i915:: Disable FBC on SandyBridge

[Daniel Vetter]

On Tue, Nov 08, 2011 at 11:17:34PM +0000, Chris Wilson wrote:
> Enabling FBC is causing the BLT ring to run between 10-100x slower than
> normal and frequently lockup. The interim solution is disable FBC once
> more until we know why.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Iirc fbc isn't really worth it power-wise on snb and we don't implement it on
ivb. So shouldn't we just disable it completely? Eugeni, any opinions - I
think you're most up to speed on power saving figures for snb?
-Daniel
> ---
>  drivers/gpu/drm/i915/intel_display.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 9fa342e..f972a09 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -1864,7 +1864,7 @@ static void intel_update_fbc(struct drm_device *dev)
>  	if (enable_fbc < 0) {
>  		DRM_DEBUG_KMS("fbc set to per-chip default\n");
>  		enable_fbc = 1;
> -		if (INTEL_INFO(dev)->gen <= 5)
> +		if (INTEL_INFO(dev)->gen <= 6)
>  			enable_fbc = 0;
>  	}
>  	if (!enable_fbc) {
> -- 
> 1.7.7.2
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: [PATCH] drm/i915:: Disable FBC on SandyBridge

[Chris Wilson]

On Tue, 17 Jan 2012 11:57:05 +0100, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Tue, Nov 08, 2011 at 11:17:34PM +0000, Chris Wilson wrote:
> > Enabling FBC is causing the BLT ring to run between 10-100x slower than
> > normal and frequently lockup. The interim solution is disable FBC once
> > more until we know why.
> > 
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> 
> Iirc fbc isn't really worth it power-wise on snb and we don't implement it on
> ivb. So shouldn't we just disable it completely? Eugeni, any opinions - I
> think you're most up to speed on power saving figures for snb?

Also note that I've had a couple of people confirm this bug and tested
the patch on IRC. Doesn't help explain precisely what is wrong nor if
there is a better workaround amidst the chicken bits that we've missed.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Re: [PATCH] drm/i915:: Disable FBC on SandyBridge

[Eugeni Dodonov]

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On Tue, Jan 17, 2012 at 08:57, Daniel Vetter <daniel@ffwll.ch> wrote:

> On Tue, Nov 08, 2011 at 11:17:34PM +0000, Chris Wilson wrote:
> > Enabling FBC is causing the BLT ring to run between 10-100x slower than
> > normal and frequently lockup. The interim solution is disable FBC once
> > more until we know why.
> >
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>
> Iirc fbc isn't really worth it power-wise on snb and we don't implement it
> on
> ivb. So shouldn't we just disable it completely? Eugeni, any opinions - I
> think you're most up to speed on power saving figures for snb?
>

The FBC is good in some cases and bad in others. Let me confirm with our
windows drivers friends first, but I'd say that we could disable it as it
brings no significant improvements..

-- 
Eugeni Dodonov
<http://eugeni.dodonov.net/>

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Re: [PATCH] drm/i915:: Disable FBC on SandyBridge

[Daniel Vetter]

On Tue, Jan 17, 2012 at 12:16, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> On Tue, 17 Jan 2012 11:57:05 +0100, Daniel Vetter <daniel@ffwll.ch> wrote:
>> On Tue, Nov 08, 2011 at 11:17:34PM +0000, Chris Wilson wrote:
>> > Enabling FBC is causing the BLT ring to run between 10-100x slower than
>> > normal and frequently lockup. The interim solution is disable FBC once
>> > more until we know why.
>> >
>> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>>
>> Iirc fbc isn't really worth it power-wise on snb and we don't implement it on
>> ivb. So shouldn't we just disable it completely? Eugeni, any opinions - I
>> think you're most up to speed on power saving figures for snb?
>
> Also note that I've had a couple of people confirm this bug and tested
> the patch on IRC. Doesn't help explain precisely what is wrong nor if
> there is a better workaround amidst the chicken bits that we've missed.

Keith, I think the disable-fbc-on-snb should go to -fixes. Eugeni can
meanwhile figure out whether it's worth it on ivb or not and what we
should do with this mess in -next. Hence this patch is (for -fixes)
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-Daniel
-- 
Daniel Vetter
daniel.vetter@ffwll.ch - +41 (0) 79 364 57 48 - http://blog.ffwll.ch

Re: [PATCH] drm/i915:: Disable FBC on SandyBridge

[Daniel Vetter]

On Tue, Jan 17, 2012 at 16:12, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Tue, Jan 17, 2012 at 12:16, Chris Wilson <chris@chris-wilson.co.uk> wrote:
>> On Tue, 17 Jan 2012 11:57:05 +0100, Daniel Vetter <daniel@ffwll.ch> wrote:
>>> On Tue, Nov 08, 2011 at 11:17:34PM +0000, Chris Wilson wrote:
>>> > Enabling FBC is causing the BLT ring to run between 10-100x slower than
>>> > normal and frequently lockup. The interim solution is disable FBC once
>>> > more until we know why.
>>> >
>>> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>>>
>>> Iirc fbc isn't really worth it power-wise on snb and we don't implement it on
>>> ivb. So shouldn't we just disable it completely? Eugeni, any opinions - I
>>> think you're most up to speed on power saving figures for snb?
>>
>> Also note that I've had a couple of people confirm this bug and tested
>> the patch on IRC. Doesn't help explain precisely what is wrong nor if
>> there is a better workaround amidst the chicken bits that we've missed.
>
> Keith, I think the disable-fbc-on-snb should go to -fixes. Eugeni can
> meanwhile figure out whether it's worth it on ivb or not and what we
> should do with this mess in -next. Hence this patch is (for -fixes)
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Hi Keith, looks like I've forgotten to add you to the cc list. Can you
pick this one up for -fixes?
-Daniel
-- 
Daniel Vetter
daniel.vetter@ffwll.ch - +41 (0) 79 364 57 48 - http://blog.ffwll.ch

Re: [PATCH] drm/i915:: Disable FBC on SandyBridge

[Keith Packard]

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On Thu, 26 Jan 2012 15:31:38 +0100, Daniel Vetter <daniel@ffwll.ch> wrote:

> Hi Keith, looks like I've forgotten to add you to the cc list. Can you
> pick this one up for -fixes?

Will do.

-- 
keith.packard@intel.com

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Re: [PATCH] drm/i915:: Disable FBC on SandyBridge

[Keith Packard]

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On Tue,  8 Nov 2011 23:17:34 +0000, Chris Wilson <chris@chris-wilson.co.uk> wrote:

> Enabling FBC is causing the BLT ring to run between 10-100x slower than
> normal and frequently lockup. The interim solution is disable FBC once
> more until we know why.

I've pushed this to drm-intel-fixes-next (we're currently waiting for
drm-intel-fixes to be merged to drm-fixes)

-- 
keith.packard@intel.com

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