Re: [Intel-gfx] [PATCH] drm/i915: Abstract display info away during probe

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 02 Oct 2023, Rodrigo Vivi <rodrigo.vivi@intel.com> wrote:
> On Mon, Oct 02, 2023 at 10:41:14AM +0300, Jani Nikula wrote:
>> On Fri, 29 Sep 2023, Rodrigo Vivi <rodrigo.vivi@intel.com> wrote:
>> > The goal is to have this function ready for Xe to use
>> > directly. So, let's use the available macro.
>> 
>> Seesm wrong to use DISPLAY_INFO() as an lvalue
>
> to be really honestly I don't like that either.
> I barely like macros, specially used like this.
>
>> and I'm not sure why
>> this wouldn't work as-is.
>
> I should probably had collected some logs and added to the
> commit message. But the thing was that without this assignment,
> (xe)->info.display was NULL and the memcpy below was exploding
> with NULL dereference.

Aww crap. That's because both DISPLAY_INFO() and DISPLAY_RUNTIME_INFO()
in xe are completely bogus.

They should be

#define DISPLAY_INFO(i915)	((i915)->display.info.__device_info)
#define DISPLAY_RUNTIME_INFO(i915)	(&(i915)->display.info.__runtime_info)

instead of

#define DISPLAY_INFO(xe)		((xe)->info.display)
#define DISPLAY_RUNTIME_INFO(xe)	(&(xe)->info.display_runtime)

and these should be removed from struct xe_device info member:

		const struct intel_display_device_info *display;
		struct intel_display_runtime_info display_runtime;

BR,
Jani.


>
>> 
>> But *shrug*.
>> 
>> Reviewed-by: Jani Nikula <jani.nikula@intel.com>
>
> thanks, pushed as is.
>
>> 
>> for merging to i915. (xe should come as a backport with cherry-pick -x.)
>
> and sent the proper backported cherry-pick to intel-xe ml.
>
>> 
>> BR,
>> Jani
>> 
>> 
>> >
>> > Cc: Jani Nikula <jani.nikula@intel.com>
>> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/display/intel_display_device.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_display_device.c b/drivers/gpu/drm/i915/display/intel_display_device.c
>> > index a6a18eae7ae8..ce55b968e658 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_display_device.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_display_device.c
>> > @@ -926,7 +926,7 @@ void intel_display_device_probe(struct drm_i915_private *i915)
>> >  	else
>> >  		info = probe_display(i915);
>> >  
>> > -	i915->display.info.__device_info = info;
>> > +	DISPLAY_INFO(i915) = info;
>> >  
>> >  	memcpy(DISPLAY_RUNTIME_INFO(i915),
>> >  	       &DISPLAY_INFO(i915)->__runtime_defaults,
>> 
>> -- 
>> Jani Nikula, Intel

-- 
Jani Nikula, Intel