Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> writes:
> On Tue, Sep 25, 2018 at 04:38:03PM +0300, Mika Kuoppala wrote:
>> Using fbc with VT-d flickers also on kbl and cfl.
>>
>> Cc: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
>> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
>> Cc: <stable@xxxxxxxxxxxxxxx> # v4.9+
>> Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
>> ---
>> drivers/gpu/drm/i915/intel_fbc.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
>> index 74d425c700ef..a149f08c1b79 100644
>> --- a/drivers/gpu/drm/i915/intel_fbc.c
>> +++ b/drivers/gpu/drm/i915/intel_fbc.c
>> @@ -1275,9 +1275,10 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
>>
>> static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv)
>> {
>> - /* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */
>> + /* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt,kbl,cfl */
>
> The hsds seem to be saying that this was fixed in kbl/cnl. I guess the
> flicker could be due to a different vt-d vs. fbc issue.
>
I was trusting the wa database on this one.
> Is the chicken bit in CHICKEN_PIPESL in the correct position?
Yes it is zero.
>
> Hmm. Bspec doesn't list chicken bit for glk. That would seem to suggest
> that we need this w/a for glk as well.
Agreed. The questio is that should we follow bspec and logic or
leave it until we get a report if it is a problem?
cfl is close enough|similar in this respect that we mimic
kbl with it?
Thanks,
-Mika
>
>> if (intel_vtd_active() &&
>> - (IS_SKYLAKE(dev_priv) || IS_BROXTON(dev_priv))) {
>> + (IS_SKYLAKE(dev_priv) || IS_BROXTON(dev_priv) ||
>> + IS_KABYLAKE(dev_priv) || IS_COFFEELAKE(dev_priv))) {
>> DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n");
>> return true;
>> }
>> --
>> 2.17.1
>
> --
> Ville Syrjälä
> Intel
