Re: [PATCH v5 3/3] drm/xe/guc/tlb: Flush g2h worker in case of tlb timeout

[John Harrison <john.c.harrison@intel.com>]

On 10/29/2024 05:01, Nirmoy Das wrote:
> Flush the g2h worker explicitly if TLB timeout happens which is
> observed on LNL and that points to the recent scheduling issue with
> E-cores on LNL.
>
> 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)
> v3: Remove gfx platform check as the issue related to cpu
>      platform(John)
>      Use the common WA macro(John) and print when the flush
>      resolves timeout(Matt B)
> v4: Remove the resolves log and do the flush before taking
>      pending_lock(Matt A)
>
> Cc: Badal Nilawar <badal.nilawar@intel.com>
> Cc: Matthew Brost <matthew.brost@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/2687
> Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
> index 773de1f08db9..3cb228c773cd 100644
> --- a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
> +++ b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
> @@ -72,6 +72,8 @@ static void xe_gt_tlb_fence_timeout(struct work_struct *work)
>   	struct xe_device *xe = gt_to_xe(gt);
>   	struct xe_gt_tlb_invalidation_fence *fence, *next;
>   
> +	LNL_FLUSH_WORK(&gt->uc.guc.ct.g2h_worker);
> +
Do we not want some kind of 'success required flush' message here as per 
the other instances?

John.

>   	spin_lock_irq(&gt->tlb_invalidation.pending_lock);
>   	list_for_each_entry_safe(fence, next,
>   				 &gt->tlb_invalidation.pending_fences, link) {