[Intel-gfx] [PATCH] drm/i915: Enable FBC on GEN7 by default

[Stéphane Marchesin]

On Mon, Mar 24, 2014 at 6:46 PM, Ben Widawsky <ben at bwidawsk.net> wrote:
> On Mon, Mar 24, 2014 at 06:41:47PM -0700, Stéphane Marchesin wrote:
>> On Mon, Mar 24, 2014 at 6:21 PM, Ben Widawsky
>> <benjamin.widawsky at linux.intel.com> wrote:
>> > I am not clear why we've never enabled it by default for GEN7. Looking
>> > at the git hostiry, it seems Rodrigo disabled it by default, and it's
>> > never been turned on. Quite a few fixes have gone in over the past year,
>> > and I think many of us are running this successfully.
>>
>> Did you try with a high resolution panel? I could never get IVB FBC to
>> be completely stable with a 2560x1700 panel...
>>
>> Stéphane
>
> 1600x900 is working fine. At my current laziness, that's the best I can
> test. I can try on a higher resolution tomorrow.  Perhaps the solution
> would be to disable if the resolution goes above a certain point.
>
> Honestly, I assumed there was a reason it was disabled, I just couldn't
> find it.

For what it's worth, it's fine for me up to 2k wide. Things seem to go
bad above that.

Stéphane

>
>>
>> >
>> > If there is some reason we know of why we don't enable this by default
>> > on GEN7, then please ignore the patch, and forgive my laziness.
>> >
>> > Cc: Rodrigo Vivi <rodrigo.vivi at gmail.com>
>> > Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
>> > ---
>> >  drivers/gpu/drm/i915/intel_pm.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>> > index a7da962..a9890df 100644
>> > --- a/drivers/gpu/drm/i915/intel_pm.c
>> > +++ b/drivers/gpu/drm/i915/intel_pm.c
>> > @@ -512,7 +512,7 @@ void intel_update_fbc(struct drm_device *dev)
>> >         adjusted_mode = &intel_crtc->config.adjusted_mode;
>> >
>> >         if (i915.enable_fbc < 0 &&
>> > -           INTEL_INFO(dev)->gen <= 7 && !IS_HASWELL(dev)) {
>> > +           INTEL_INFO(dev)->gen <= 6) {
>> >                 if (set_no_fbc_reason(dev_priv, FBC_CHIP_DEFAULT))
>> >                         DRM_DEBUG_KMS("disabled per chip default\n");
>> >                 goto out_disable;
>> > --
>> > 1.9.1
>> >
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>
> --
> Ben Widawsky, Intel Open Source Technology Center