[Intel-gfx] [PATCH] drm/i915/uc: Fini hw even if GuC is not running

[Daniele Ceraolo Spurio]

On 8/13/19 9:26 AM, Fernando Pacheco wrote:
> We should not be skipping uc_fini_hw on finding GuC
> is no longer running. There is plenty of hw and internal
> state that can be cleaned up without having to communicate
> with GuC.
> 

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110943

> Signed-off-by: Fernando Pacheco <fernando.pacheco at intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> ---
>   drivers/gpu/drm/i915/gt/uc/intel_uc.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> index 0dc2b0cf4604..c698cddc14dc 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> @@ -521,7 +521,7 @@ void intel_uc_fini_hw(struct intel_uc *uc)
>   {
>   	struct intel_guc *guc = &uc->guc;
>   
> -	if (!intel_guc_is_running(guc))
> +	if (!intel_uc_supports_guc(uc))

Both calls below handle the case where GuC is already not running so 
we're safe, but now that we wedge when we hit a guc error we can also do 
something like:

	-EIO load error -> uc_fini_hw() -> wedge
and then
	unload -> uc_fini_hw()

it should be all be handled safely (the fault injection test is passing 
where we've run it), but we end up with "GuC communication disabled" 
multiple times in the logs:

https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_13999/fi-skl-guc/igt@i915_module_load@reload-with-fault-injection.html

<6> [237.818905] [drm] GuC communication enabled
....
<6> [237.822739] i915 0000:00:02.0: [drm:__i915_inject_load_error 
[i915]] Injecting failure -5 at checkpoint 44 [i915_gem_init:1503]
<6> [237.840808] [drm] GuC communication disabled
...
<6> [238.160935] [drm] GuC communication disabled

Maybe return early from guc_disable_communication if the communication 
was already disabled?

Daniele

>   		return;
>   
>   	if (intel_uc_supports_guc_submission(uc))
>