[Intel-gfx] [PATCH RFC] drm/i915: reduce cursor size for GEN5 hardware

[Maarten Lankhorst]

Op 31-01-17 om 20:13 schreef Uwe Kleine-König:
> Hello,
>
> On Tue, Jan 31, 2017 at 10:03:26AM +0100, Maarten Lankhorst wrote:
>> Op 31-01-17 om 09:09 schreef Uwe Kleine-König:
>>> From: Chris Wilson <chris at chris-wilson.co.uk>
>>>
>>> As the introduced comment admits this is clearly a workaround, but for
>>> me this is the only known way to make my Lenovo X201 work without
>>> flickering and crashing.
>>>
>>> Signed-off-by: Uwe Kleine-König <uwe at kleine-koenig.org>
>>> [uwe: added changelog, comment and restrict to GEN5]
>>> ---
>>> Hello,
>>>
>>> as I don't like having to compile my own kernel (which has this workaround) I
>>> suggest to apply this patch until someone with more knowledge than me about
>>> i915 finds the muse and time to work on this.
>> Just curious, does this help?
>>
>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>> index ae2c0bb4b2e8..13de4c526ca6 100644
>> --- a/drivers/gpu/drm/i915/intel_pm.c
>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>> @@ -1838,7 +1838,7 @@ static uint32_t ilk_compute_cur_wm(const struct intel_crtc_state *cstate,
>>  	 * this is necessary to avoid flickering.
>>  	 */
>>  	int cpp = 4;
>> -	int width = pstate->base.visible ? pstate->base.crtc_w : 64;
>> +	int width = 256;
>>  
>>  	if (!cstate->base.active)
>>  		return 0;
>>
> On a kernel with this patch applied I cannot reproduce the flickering. I
> keep that kernel running but expect that it also fixes the crash.
>
> Best regards
> Uwe

Ok that's good news.

Maybe ville or matt can comment whether this patch is the right fix?