Re: [PATCH v2] drm/xe/ufence: Flush xe ordered_wq in case of ufence timeout

[Nirmoy Das <nirmoy.das@linux.intel.com>]

On 10/24/2024 6:32 PM, Jani Nikula wrote:
> On Thu, 24 Oct 2024, Nirmoy Das <nirmoy.das@intel.com> wrote:
>> Flush xe ordered_wq in case of ufence timeout which is observed
>> on LNL and that points to the recent scheduling issue with E-cores.
>>
>> This is similar to the recent fix:
>> commit e51527233804 ("drm/xe/guc/ct: Flush g2h worker in case of g2h
>> response timeout") and should be removed once there is E core
>> scheduling fix.
>>
>> v2: Add platform check(Himal)
>>     s/__flush_workqueue/flush_workqueue(Jani)
>>
>> Cc: Badal Nilawar <badal.nilawar@intel.com>
>> Cc: Jani Nikula <jani.nikula@intel.com>
>> Cc: Matthew Auld <matthew.auld@intel.com>
>> Cc: John Harrison <John.C.Harrison@Intel.com>
>> Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
>> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
>> Cc: <stable@vger.kernel.org> # v6.11+
>> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2754
>> Suggested-by: Matthew Brost <matthew.brost@intel.com>
>> Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
>> Reviewed-by: Matthew Brost <matthew.brost@intel.com>
>> ---
>>  drivers/gpu/drm/xe/xe_wait_user_fence.c | 14 ++++++++++++++
>>  1 file changed, 14 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_wait_user_fence.c b/drivers/gpu/drm/xe/xe_wait_user_fence.c
>> index f5deb81eba01..78a0ad3c78fe 100644
>> --- a/drivers/gpu/drm/xe/xe_wait_user_fence.c
>> +++ b/drivers/gpu/drm/xe/xe_wait_user_fence.c
>> @@ -13,6 +13,7 @@
>>  #include "xe_device.h"
>>  #include "xe_gt.h"
>>  #include "xe_macros.h"
>> +#include "compat-i915-headers/i915_drv.h"
> Sorry, you just can't use this in xe core. At all. Not even a little
> bit. It's purely for i915 display compat code.
>
> If you need it for the LNL platform check, you need to use:
>
> 	xe->info.platform == XE_LUNARLAKE


Will do that. That macro looked odd but I didn't know a better way.

>
> Although platform checks in xe code are generally discouraged.


This issue unfortunately depending on platform instead of graphics IP.


Thanks,

Nirmoy

>
> BR,
> Jani.
>
>
>
>>  #include "xe_exec_queue.h"
>>  
>>  static int do_compare(u64 addr, u64 value, u64 mask, u16 op)
>> @@ -155,6 +156,19 @@ int xe_wait_user_fence_ioctl(struct drm_device *dev, void *data,
>>  		}
>>  
>>  		if (!timeout) {
>> +			if (IS_LUNARLAKE(xe)) {
>> +				/*
>> +				 * This is analogous to e51527233804 ("drm/xe/guc/ct: Flush g2h
>> +				 * worker in case of g2h response timeout")
>> +				 *
>> +				 * TODO: Drop this change once workqueue scheduling delay issue is
>> +				 * fixed on LNL Hybrid CPU.
>> +				 */
>> +				flush_workqueue(xe->ordered_wq);
>> +				err = do_compare(addr, args->value, args->mask, args->op);
>> +				if (err <= 0)
>> +					break;
>> +			}
>>  			err = -ETIME;
>>  			break;
>>  		}