Re: [PATCH] drm/xe: Revert "drm/i915: Disable DSB in Xe KMD"

[Matthew Auld <matthew.auld@intel.com>]

On 09/07/2024 10:33, Maarten Lankhorst wrote:
> Hello,
> 
> I've been trying out this patch, but I'm still seeing corruption on my laptop with DSB enabled.
> I'd recommend not merging until it is fixed. :)

Just wondering, is it correct to use cpu:wb for the dsb buffer? Does the 
dsb stuff not suffer from "display is not coherent with gpu/cpu caches"? 
In i915 it looks to be cpu:wc.

> 
> Cheers,
> ~Maarten
> 
> Den 2024-07-08 kl. 07:56, skrev Animesh Manna:
>> This reverts commit c27f010aa1884276ee5dae72034d84987060c769.
>>
>> After fix from [1] dsb timeout issue is not reproducible on local testing
>> with xe driver. Checking CI result to confirm and not for review.
>>
>> [1] https://patchwork.freedesktop.org/series/130783/
>>
>> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
>> ---
>>   drivers/gpu/drm/i915/display/intel_dsb.c | 4 ----
>>   1 file changed, 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
>> index 2ab3765f6c06..e9c4835a2c30 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
>> @@ -463,10 +463,6 @@ struct intel_dsb *intel_dsb_prepare(struct intel_atomic_state *state,
>>   	if (!i915->display.params.enable_dsb)
>>   		return NULL;
>>   
>> -	/* TODO: DSB is broken in Xe KMD, so disabling it until fixed */
>> -	if (!IS_ENABLED(I915))
>> -		return NULL;
>> -
>>   	dsb = kzalloc(sizeof(*dsb), GFP_KERNEL);
>>   	if (!dsb)
>>   		goto out;