Re: [PATCH] drm/xe/client: Check return value of xe_force_wake_get

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Wed, May 29, 2024 at 10:50:34AM +0200, Nirmoy Das wrote:
> Hi Rodrigo,
> 
> On 5/28/2024 7:22 PM, Rodrigo Vivi wrote:
> > On Tue, May 28, 2024 at 12:11:32PM +0200, Nirmoy Das wrote:
> > > xe_force_wake_get() can return error so check it's return value
> > > before reading gpu_timestamp value.
> > > 
> > > Fixes: 188ced1e0ff8 ("drm/xe/client: Print runtime to fdinfo")
> > > Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> > > Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
> > > ---
> > >   drivers/gpu/drm/xe/xe_drm_client.c | 6 ++++--
> > >   1 file changed, 4 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/xe/xe_drm_client.c b/drivers/gpu/drm/xe/xe_drm_client.c
> > > index 4a19b771e3a0..0c13395ffd34 100644
> > > --- a/drivers/gpu/drm/xe/xe_drm_client.c
> > > +++ b/drivers/gpu/drm/xe/xe_drm_client.c
> > > @@ -245,7 +245,7 @@ static void show_run_ticks(struct drm_printer *p, struct drm_file *file)
> > >   	struct xe_gt *gt;
> > >   	struct xe_hw_engine *hwe;
> > >   	struct xe_exec_queue *q;
> > > -	u64 gpu_timestamp;
> > > +	u64 gpu_timestamp = 0;
> > >   	xe_pm_runtime_get(xe);
> > > @@ -264,7 +264,9 @@ static void show_run_ticks(struct drm_printer *p, struct drm_file *file)
> > >   		if (!hwe)
> > >   			continue;
> > > -		xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
> > > +		if (xe_force_wake_get(gt_to_fw(gt), XE_FW_GT))
> > > +			break;
> > worth adding a debug/err msg?
> 
> xe_force_wake_get() will throw a drm_notice on error. May be we should add a
> __builtin_return_address() in xe_force_wake_get() to know the caller as
> 
> the current pattern seems to be to just return early on error ?

indeed. please ignore me and sorry for the noise.

> 
> > 
> > but up to you:
> > 
> > Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> 
> Thanks,
> 
> Nirmoy
> 
> > 
> > > +
> > >   		gpu_timestamp = xe_hw_engine_read_timestamp(hwe);
> > >   		xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
> > >   		break;
> > > -- 
> > > 2.42.0
> > >