drm/i915/gen9: fix error path in intel_init_workaround_bb
diff mbox

Message ID 1435069573-29624-1-git-send-email-imre.deak@intel.com
State New
Headers show

Commit Message

Imre Deak June 23, 2015, 2:26 p.m. UTC
On the GEN!=8 error path we call kmap_atomic() which returns in atomic
context and then lrc_destroy_wa_ctx_obj() which can be called only in
process context. Fix this by preserving the correct cleanup order on
this error path.

Also convert the WARN to DRM_ERROR the stack trace isn't really useful.

Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Comments

Chris Wilson June 23, 2015, 2:31 p.m. UTC | #1
On Tue, Jun 23, 2015 at 05:26:13PM +0300, Imre Deak wrote:
> On the GEN!=8 error path we call kmap_atomic() which returns in atomic
> context and then lrc_destroy_wa_ctx_obj() which can be called only in
> process context. Fix this by preserving the correct cleanup order on
> this error path.
> 
> Also convert the WARN to DRM_ERROR the stack trace isn't really useful.
> 
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 1b50dd7..8bff1a2 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -1289,10 +1289,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *ring)
>  		if (ret)
>  			goto out;
>  	} else {
> -		WARN(INTEL_INFO(ring->dev)->gen >= 8,
> -		     "WA batch buffer is not initialized for Gen%d\n",
> -		     INTEL_INFO(ring->dev)->gen);
> +		if (INTEL_INFO(ring->dev)->gen >= 8)
> +			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
> +				  INTEL_INFO(ring->dev)->gen);
> +

Do this test upfront, then we don't have multiple error paths.
http://paste.debian.net/255769
-Chris
Imre Deak June 23, 2015, 2:36 p.m. UTC | #2
On ti, 2015-06-23 at 15:31 +0100, Chris Wilson wrote:
> On Tue, Jun 23, 2015 at 05:26:13PM +0300, Imre Deak wrote:
> > On the GEN!=8 error path we call kmap_atomic() which returns in atomic
> > context and then lrc_destroy_wa_ctx_obj() which can be called only in
> > process context. Fix this by preserving the correct cleanup order on
> > this error path.
> > 
> > Also convert the WARN to DRM_ERROR the stack trace isn't really useful.
> > 
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
> >  1 file changed, 7 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> > index 1b50dd7..8bff1a2 100644
> > --- a/drivers/gpu/drm/i915/intel_lrc.c
> > +++ b/drivers/gpu/drm/i915/intel_lrc.c
> > @@ -1289,10 +1289,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *ring)
> >  		if (ret)
> >  			goto out;
> >  	} else {
> > -		WARN(INTEL_INFO(ring->dev)->gen >= 8,
> > -		     "WA batch buffer is not initialized for Gen%d\n",
> > -		     INTEL_INFO(ring->dev)->gen);
> > +		if (INTEL_INFO(ring->dev)->gen >= 8)
> > +			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
> > +				  INTEL_INFO(ring->dev)->gen);
> > +
> 
> Do this test upfront, then we don't have multiple error paths.
> http://paste.debian.net/255769

I didn't bother moving it, I suppose GEN9 support will be added soon
anyway and we get a bit more test coverage on GEN9 meanwhile. But if you
insist I can move it.

> -Chris
>
arun.siluvery@linux.intel.com June 23, 2015, 3:13 p.m. UTC | #3
On 23/06/2015 15:36, Imre Deak wrote:
> On ti, 2015-06-23 at 15:31 +0100, Chris Wilson wrote:
>> On Tue, Jun 23, 2015 at 05:26:13PM +0300, Imre Deak wrote:
>>> On the GEN!=8 error path we call kmap_atomic() which returns in atomic
>>> context and then lrc_destroy_wa_ctx_obj() which can be called only in
>>> process context. Fix this by preserving the correct cleanup order on
>>> this error path.
>>>
>>> Also convert the WARN to DRM_ERROR the stack trace isn't really useful.
>>>
>>> Signed-off-by: Imre Deak <imre.deak@intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
>>>   1 file changed, 7 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
>>> index 1b50dd7..8bff1a2 100644
>>> --- a/drivers/gpu/drm/i915/intel_lrc.c
>>> +++ b/drivers/gpu/drm/i915/intel_lrc.c
>>> @@ -1289,10 +1289,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *ring)
>>>   		if (ret)
>>>   			goto out;
>>>   	} else {
>>> -		WARN(INTEL_INFO(ring->dev)->gen >= 8,
>>> -		     "WA batch buffer is not initialized for Gen%d\n",
>>> -		     INTEL_INFO(ring->dev)->gen);
>>> +		if (INTEL_INFO(ring->dev)->gen >= 8)
>>> +			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
>>> +				  INTEL_INFO(ring->dev)->gen);
>>> +
>>
>> Do this test upfront, then we don't have multiple error paths.
>> http://paste.debian.net/255769
>
> I didn't bother moving it, I suppose GEN9 support will be added soon
> anyway and we get a bit more test coverage on GEN9 meanwhile. But if you
> insist I can move it.

Hi Imre,

I sent the following patch with the changes suggested by Chris.
https://patchwork.kernel.org/patch/6661891/
Since you sent it first, my patch can be ignored if your patch is updated.

regards
Arun

>
>> -Chris
>>
>
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
Imre Deak June 23, 2015, 3:18 p.m. UTC | #4
On ti, 2015-06-23 at 16:13 +0100, Siluvery, Arun wrote:
> On 23/06/2015 15:36, Imre Deak wrote:
> > On ti, 2015-06-23 at 15:31 +0100, Chris Wilson wrote:
> >> On Tue, Jun 23, 2015 at 05:26:13PM +0300, Imre Deak wrote:
> >>> On the GEN!=8 error path we call kmap_atomic() which returns in atomic
> >>> context and then lrc_destroy_wa_ctx_obj() which can be called only in
> >>> process context. Fix this by preserving the correct cleanup order on
> >>> this error path.
> >>>
> >>> Also convert the WARN to DRM_ERROR the stack trace isn't really useful.
> >>>
> >>> Signed-off-by: Imre Deak <imre.deak@intel.com>
> >>> ---
> >>>   drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
> >>>   1 file changed, 7 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> >>> index 1b50dd7..8bff1a2 100644
> >>> --- a/drivers/gpu/drm/i915/intel_lrc.c
> >>> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> >>> @@ -1289,10 +1289,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *ring)
> >>>   		if (ret)
> >>>   			goto out;
> >>>   	} else {
> >>> -		WARN(INTEL_INFO(ring->dev)->gen >= 8,
> >>> -		     "WA batch buffer is not initialized for Gen%d\n",
> >>> -		     INTEL_INFO(ring->dev)->gen);
> >>> +		if (INTEL_INFO(ring->dev)->gen >= 8)
> >>> +			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
> >>> +				  INTEL_INFO(ring->dev)->gen);
> >>> +
> >>
> >> Do this test upfront, then we don't have multiple error paths.
> >> http://paste.debian.net/255769
> >
> > I didn't bother moving it, I suppose GEN9 support will be added soon
> > anyway and we get a bit more test coverage on GEN9 meanwhile. But if you
> > insist I can move it.
> 
> Hi Imre,
> 
> I sent the following patch with the changes suggested by Chris.
> https://patchwork.kernel.org/patch/6661891/
> Since you sent it first, my patch can be ignored if your patch is updated.

I'm fine applying your patch, but I would ask to convert the WARN to
DRM_ERROR. The stack trace doesn't add much to the error message and the
WARN is needlessly verbose now on BXT,SKL..

--Imre
Chris Wilson June 23, 2015, 3:44 p.m. UTC | #5
On Tue, Jun 23, 2015 at 06:18:21PM +0300, Imre Deak wrote:
> On ti, 2015-06-23 at 16:13 +0100, Siluvery, Arun wrote:
> > On 23/06/2015 15:36, Imre Deak wrote:
> > > On ti, 2015-06-23 at 15:31 +0100, Chris Wilson wrote:
> > >> On Tue, Jun 23, 2015 at 05:26:13PM +0300, Imre Deak wrote:
> > >>> On the GEN!=8 error path we call kmap_atomic() which returns in atomic
> > >>> context and then lrc_destroy_wa_ctx_obj() which can be called only in
> > >>> process context. Fix this by preserving the correct cleanup order on
> > >>> this error path.
> > >>>
> > >>> Also convert the WARN to DRM_ERROR the stack trace isn't really useful.
> > >>>
> > >>> Signed-off-by: Imre Deak <imre.deak@intel.com>
> > >>> ---
> > >>>   drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
> > >>>   1 file changed, 7 insertions(+), 3 deletions(-)
> > >>>
> > >>> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> > >>> index 1b50dd7..8bff1a2 100644
> > >>> --- a/drivers/gpu/drm/i915/intel_lrc.c
> > >>> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> > >>> @@ -1289,10 +1289,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *ring)
> > >>>   		if (ret)
> > >>>   			goto out;
> > >>>   	} else {
> > >>> -		WARN(INTEL_INFO(ring->dev)->gen >= 8,
> > >>> -		     "WA batch buffer is not initialized for Gen%d\n",
> > >>> -		     INTEL_INFO(ring->dev)->gen);
> > >>> +		if (INTEL_INFO(ring->dev)->gen >= 8)
> > >>> +			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
> > >>> +				  INTEL_INFO(ring->dev)->gen);
> > >>> +
> > >>
> > >> Do this test upfront, then we don't have multiple error paths.
> > >> http://paste.debian.net/255769
> > >
> > > I didn't bother moving it, I suppose GEN9 support will be added soon
> > > anyway and we get a bit more test coverage on GEN9 meanwhile. But if you
> > > insist I can move it.
> > 
> > Hi Imre,
> > 
> > I sent the following patch with the changes suggested by Chris.
> > https://patchwork.kernel.org/patch/6661891/
> > Since you sent it first, my patch can be ignored if your patch is updated.
> 
> I'm fine applying your patch, but I would ask to convert the WARN to
> DRM_ERROR. The stack trace doesn't add much to the error message and the
> WARN is needlessly verbose now on BXT,SKL..

I presumed Arun choose WARN because we are missing w/a and wanted
someone to step forward and prove the fixes?
-Chris
Imre Deak June 23, 2015, 3:58 p.m. UTC | #6
On ti, 2015-06-23 at 16:44 +0100, Chris Wilson wrote:
> On Tue, Jun 23, 2015 at 06:18:21PM +0300, Imre Deak wrote:
> > On ti, 2015-06-23 at 16:13 +0100, Siluvery, Arun wrote:
> > > On 23/06/2015 15:36, Imre Deak wrote:
> > > > On ti, 2015-06-23 at 15:31 +0100, Chris Wilson wrote:
> > > >> On Tue, Jun 23, 2015 at 05:26:13PM +0300, Imre Deak wrote:
> > > >>> On the GEN!=8 error path we call kmap_atomic() which returns in atomic
> > > >>> context and then lrc_destroy_wa_ctx_obj() which can be called only in
> > > >>> process context. Fix this by preserving the correct cleanup order on
> > > >>> this error path.
> > > >>>
> > > >>> Also convert the WARN to DRM_ERROR the stack trace isn't really useful.
> > > >>>
> > > >>> Signed-off-by: Imre Deak <imre.deak@intel.com>
> > > >>> ---
> > > >>>   drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
> > > >>>   1 file changed, 7 insertions(+), 3 deletions(-)
> > > >>>
> > > >>> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> > > >>> index 1b50dd7..8bff1a2 100644
> > > >>> --- a/drivers/gpu/drm/i915/intel_lrc.c
> > > >>> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> > > >>> @@ -1289,10 +1289,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *ring)
> > > >>>   		if (ret)
> > > >>>   			goto out;
> > > >>>   	} else {
> > > >>> -		WARN(INTEL_INFO(ring->dev)->gen >= 8,
> > > >>> -		     "WA batch buffer is not initialized for Gen%d\n",
> > > >>> -		     INTEL_INFO(ring->dev)->gen);
> > > >>> +		if (INTEL_INFO(ring->dev)->gen >= 8)
> > > >>> +			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
> > > >>> +				  INTEL_INFO(ring->dev)->gen);
> > > >>> +
> > > >>
> > > >> Do this test upfront, then we don't have multiple error paths.
> > > >> http://paste.debian.net/255769
> > > >
> > > > I didn't bother moving it, I suppose GEN9 support will be added soon
> > > > anyway and we get a bit more test coverage on GEN9 meanwhile. But if you
> > > > insist I can move it.
> > > 
> > > Hi Imre,
> > > 
> > > I sent the following patch with the changes suggested by Chris.
> > > https://patchwork.kernel.org/patch/6661891/
> > > Since you sent it first, my patch can be ignored if your patch is updated.
> > 
> > I'm fine applying your patch, but I would ask to convert the WARN to
> > DRM_ERROR. The stack trace doesn't add much to the error message and the
> > WARN is needlessly verbose now on BXT,SKL..
> 
> I presumed Arun choose WARN because we are missing w/a and wanted
> someone to step forward and prove the fixes?

Imo it's unnecessarily verbose, during development when loading the
driver I know that things are mostly ok if I can't see any such
backtraces. But no strong opinion, I can also change this locally.

--Imre
Chris Wilson June 23, 2015, 4:01 p.m. UTC | #7
On Tue, Jun 23, 2015 at 06:58:42PM +0300, Imre Deak wrote:
> On ti, 2015-06-23 at 16:44 +0100, Chris Wilson wrote:
> > On Tue, Jun 23, 2015 at 06:18:21PM +0300, Imre Deak wrote:
> > > On ti, 2015-06-23 at 16:13 +0100, Siluvery, Arun wrote:
> > > > On 23/06/2015 15:36, Imre Deak wrote:
> > > > > On ti, 2015-06-23 at 15:31 +0100, Chris Wilson wrote:
> > > > >> On Tue, Jun 23, 2015 at 05:26:13PM +0300, Imre Deak wrote:
> > > > >>> On the GEN!=8 error path we call kmap_atomic() which returns in atomic
> > > > >>> context and then lrc_destroy_wa_ctx_obj() which can be called only in
> > > > >>> process context. Fix this by preserving the correct cleanup order on
> > > > >>> this error path.
> > > > >>>
> > > > >>> Also convert the WARN to DRM_ERROR the stack trace isn't really useful.
> > > > >>>
> > > > >>> Signed-off-by: Imre Deak <imre.deak@intel.com>
> > > > >>> ---
> > > > >>>   drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
> > > > >>>   1 file changed, 7 insertions(+), 3 deletions(-)
> > > > >>>
> > > > >>> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> > > > >>> index 1b50dd7..8bff1a2 100644
> > > > >>> --- a/drivers/gpu/drm/i915/intel_lrc.c
> > > > >>> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> > > > >>> @@ -1289,10 +1289,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *ring)
> > > > >>>   		if (ret)
> > > > >>>   			goto out;
> > > > >>>   	} else {
> > > > >>> -		WARN(INTEL_INFO(ring->dev)->gen >= 8,
> > > > >>> -		     "WA batch buffer is not initialized for Gen%d\n",
> > > > >>> -		     INTEL_INFO(ring->dev)->gen);
> > > > >>> +		if (INTEL_INFO(ring->dev)->gen >= 8)
> > > > >>> +			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
> > > > >>> +				  INTEL_INFO(ring->dev)->gen);
> > > > >>> +
> > > > >>
> > > > >> Do this test upfront, then we don't have multiple error paths.
> > > > >> http://paste.debian.net/255769
> > > > >
> > > > > I didn't bother moving it, I suppose GEN9 support will be added soon
> > > > > anyway and we get a bit more test coverage on GEN9 meanwhile. But if you
> > > > > insist I can move it.
> > > > 
> > > > Hi Imre,
> > > > 
> > > > I sent the following patch with the changes suggested by Chris.
> > > > https://patchwork.kernel.org/patch/6661891/
> > > > Since you sent it first, my patch can be ignored if your patch is updated.
> > > 
> > > I'm fine applying your patch, but I would ask to convert the WARN to
> > > DRM_ERROR. The stack trace doesn't add much to the error message and the
> > > WARN is needlessly verbose now on BXT,SKL..
> > 
> > I presumed Arun choose WARN because we are missing w/a and wanted
> > someone to step forward and prove the fixes?
> 
> Imo it's unnecessarily verbose, during development when loading the
> driver I know that things are mostly ok if I can't see any such
> backtraces. But no strong opinion, I can also change this locally.

An alternative would be to provide the stub wa_bb emission functions so
that future wa need only start with a plain copy'n'paste.
-Chris
arun.siluvery@linux.intel.com June 23, 2015, 4:21 p.m. UTC | #8
On 23/06/2015 17:01, Chris Wilson wrote:
> On Tue, Jun 23, 2015 at 06:58:42PM +0300, Imre Deak wrote:
>> On ti, 2015-06-23 at 16:44 +0100, Chris Wilson wrote:
>>> On Tue, Jun 23, 2015 at 06:18:21PM +0300, Imre Deak wrote:
>>>> On ti, 2015-06-23 at 16:13 +0100, Siluvery, Arun wrote:
>>>>> On 23/06/2015 15:36, Imre Deak wrote:
>>>>>> On ti, 2015-06-23 at 15:31 +0100, Chris Wilson wrote:
>>>>>>> On Tue, Jun 23, 2015 at 05:26:13PM +0300, Imre Deak wrote:
>>>>>>>> On the GEN!=8 error path we call kmap_atomic() which returns in atomic
>>>>>>>> context and then lrc_destroy_wa_ctx_obj() which can be called only in
>>>>>>>> process context. Fix this by preserving the correct cleanup order on
>>>>>>>> this error path.
>>>>>>>>
>>>>>>>> Also convert the WARN to DRM_ERROR the stack trace isn't really useful.
>>>>>>>>
>>>>>>>> Signed-off-by: Imre Deak <imre.deak@intel.com>
>>>>>>>> ---
>>>>>>>>    drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
>>>>>>>>    1 file changed, 7 insertions(+), 3 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
>>>>>>>> index 1b50dd7..8bff1a2 100644
>>>>>>>> --- a/drivers/gpu/drm/i915/intel_lrc.c
>>>>>>>> +++ b/drivers/gpu/drm/i915/intel_lrc.c
>>>>>>>> @@ -1289,10 +1289,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *ring)
>>>>>>>>    		if (ret)
>>>>>>>>    			goto out;
>>>>>>>>    	} else {
>>>>>>>> -		WARN(INTEL_INFO(ring->dev)->gen >= 8,
>>>>>>>> -		     "WA batch buffer is not initialized for Gen%d\n",
>>>>>>>> -		     INTEL_INFO(ring->dev)->gen);
>>>>>>>> +		if (INTEL_INFO(ring->dev)->gen >= 8)
>>>>>>>> +			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
>>>>>>>> +				  INTEL_INFO(ring->dev)->gen);
>>>>>>>> +
>>>>>>>
>>>>>>> Do this test upfront, then we don't have multiple error paths.
>>>>>>> http://paste.debian.net/255769
>>>>>>
>>>>>> I didn't bother moving it, I suppose GEN9 support will be added soon
>>>>>> anyway and we get a bit more test coverage on GEN9 meanwhile. But if you
>>>>>> insist I can move it.
>>>>>
>>>>> Hi Imre,
>>>>>
>>>>> I sent the following patch with the changes suggested by Chris.
>>>>> https://patchwork.kernel.org/patch/6661891/
>>>>> Since you sent it first, my patch can be ignored if your patch is updated.
>>>>
>>>> I'm fine applying your patch, but I would ask to convert the WARN to
>>>> DRM_ERROR. The stack trace doesn't add much to the error message and the
>>>> WARN is needlessly verbose now on BXT,SKL..
>>>
>>> I presumed Arun choose WARN because we are missing w/a and wanted
>>> someone to step forward and prove the fixes?
>>
>> Imo it's unnecessarily verbose, during development when loading the
>> driver I know that things are mostly ok if I can't see any such
>> backtraces. But no strong opinion, I can also change this locally.

Error message can easily get lost and also it is not an error to not 
apply these WA which is why we also continue. I thought WARN will 
probably get more attention and help in adding missing WA quickly.

regards
Arun

>
> An alternative would be to provide the stub wa_bb emission functions so
> that future wa need only start with a plain copy'n'paste.
> -Chris
>
Daniel Vetter June 23, 2015, 9:13 p.m. UTC | #9
On Tue, Jun 23, 2015 at 05:21:16PM +0100, Siluvery, Arun wrote:
> On 23/06/2015 17:01, Chris Wilson wrote:
> >On Tue, Jun 23, 2015 at 06:58:42PM +0300, Imre Deak wrote:
> >>On ti, 2015-06-23 at 16:44 +0100, Chris Wilson wrote:
> >>>On Tue, Jun 23, 2015 at 06:18:21PM +0300, Imre Deak wrote:
> >>>>On ti, 2015-06-23 at 16:13 +0100, Siluvery, Arun wrote:
> >>>>>On 23/06/2015 15:36, Imre Deak wrote:
> >>>>>>On ti, 2015-06-23 at 15:31 +0100, Chris Wilson wrote:
> >>>>>>>On Tue, Jun 23, 2015 at 05:26:13PM +0300, Imre Deak wrote:
> >>>>>>>>On the GEN!=8 error path we call kmap_atomic() which returns in atomic
> >>>>>>>>context and then lrc_destroy_wa_ctx_obj() which can be called only in
> >>>>>>>>process context. Fix this by preserving the correct cleanup order on
> >>>>>>>>this error path.
> >>>>>>>>
> >>>>>>>>Also convert the WARN to DRM_ERROR the stack trace isn't really useful.
> >>>>>>>>
> >>>>>>>>Signed-off-by: Imre Deak <imre.deak@intel.com>
> >>>>>>>>---
> >>>>>>>>   drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++---
> >>>>>>>>   1 file changed, 7 insertions(+), 3 deletions(-)
> >>>>>>>>
> >>>>>>>>diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> >>>>>>>>index 1b50dd7..8bff1a2 100644
> >>>>>>>>--- a/drivers/gpu/drm/i915/intel_lrc.c
> >>>>>>>>+++ b/drivers/gpu/drm/i915/intel_lrc.c
> >>>>>>>>@@ -1289,10 +1289,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *ring)
> >>>>>>>>   		if (ret)
> >>>>>>>>   			goto out;
> >>>>>>>>   	} else {
> >>>>>>>>-		WARN(INTEL_INFO(ring->dev)->gen >= 8,
> >>>>>>>>-		     "WA batch buffer is not initialized for Gen%d\n",
> >>>>>>>>-		     INTEL_INFO(ring->dev)->gen);
> >>>>>>>>+		if (INTEL_INFO(ring->dev)->gen >= 8)
> >>>>>>>>+			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
> >>>>>>>>+				  INTEL_INFO(ring->dev)->gen);
> >>>>>>>>+
> >>>>>>>
> >>>>>>>Do this test upfront, then we don't have multiple error paths.
> >>>>>>>http://paste.debian.net/255769
> >>>>>>
> >>>>>>I didn't bother moving it, I suppose GEN9 support will be added soon
> >>>>>>anyway and we get a bit more test coverage on GEN9 meanwhile. But if you
> >>>>>>insist I can move it.
> >>>>>
> >>>>>Hi Imre,
> >>>>>
> >>>>>I sent the following patch with the changes suggested by Chris.
> >>>>>https://patchwork.kernel.org/patch/6661891/
> >>>>>Since you sent it first, my patch can be ignored if your patch is updated.
> >>>>
> >>>>I'm fine applying your patch, but I would ask to convert the WARN to
> >>>>DRM_ERROR. The stack trace doesn't add much to the error message and the
> >>>>WARN is needlessly verbose now on BXT,SKL..
> >>>
> >>>I presumed Arun choose WARN because we are missing w/a and wanted
> >>>someone to step forward and prove the fixes?
> >>
> >>Imo it's unnecessarily verbose, during development when loading the
> >>driver I know that things are mostly ok if I can't see any such
> >>backtraces. But no strong opinion, I can also change this locally.
> 
> Error message can easily get lost and also it is not an error to not apply
> these WA which is why we also continue. I thought WARN will probably get
> more attention and help in adding missing WA quickly.

Friendly inquiry from your maintainer: Can we perhaps not bikeshed the
benefits of DRM_ERROR vs. WARN_ON and just get this reviewed&merged?

From an igt/piglit pov both cause a test failure and so are equivalent.
And I'm hopeful that the new QA team actually catches dmesg fallout
reliable rsn.

Thanks, Daniel

Patch
diff mbox

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 1b50dd7..8bff1a2 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1289,10 +1289,14 @@  static int intel_init_workaround_bb(struct intel_engine_cs *ring)
 		if (ret)
 			goto out;
 	} else {
-		WARN(INTEL_INFO(ring->dev)->gen >= 8,
-		     "WA batch buffer is not initialized for Gen%d\n",
-		     INTEL_INFO(ring->dev)->gen);
+		if (INTEL_INFO(ring->dev)->gen >= 8)
+			DRM_ERROR("WA batch buffer is not initialized for Gen%d\n",
+				  INTEL_INFO(ring->dev)->gen);
+
+		kunmap_atomic(batch);
 		lrc_destroy_wa_ctx_obj(ring);
+
+		return 0;
 	}
 
 out: