Re: [PATCH 3/3] drm: Update documentation and TODO of gem_prime_mmap hook

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi

Am 10.11.21 um 11:46 schrieb Daniel Vetter:
> On Mon, Nov 08, 2021 at 11:28:46AM +0100, Thomas Zimmermann wrote:
>> The hook gem_prime_mmap in struct drm_driver is deprecated. Document
>> the new requirements.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> 
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Thanks a lot!

With the remaining patches merged, all drivers will implement 
gem_prime_mmap via drm_gem_prime_mmap() and use the GEM object's mmap 
callback for specific details.

The next step would be to move all custom implementations of 
file_operations.mmap into the GEM object's mmap and implement the 
file_operations callback with drm_mmap().

Best regards
Thomas

> 
>> ---
>>   Documentation/gpu/todo.rst | 11 -----------
>>   include/drm/drm_drv.h      | 11 +++++++----
>>   2 files changed, 7 insertions(+), 15 deletions(-)
>>
>> diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
>> index 60d1d7ee0719..6593c4c4006e 100644
>> --- a/Documentation/gpu/todo.rst
>> +++ b/Documentation/gpu/todo.rst
>> @@ -268,17 +268,6 @@ Contact: Daniel Vetter
>>   
>>   Level: Intermediate
>>   
>> -Clean up mmap forwarding
>> -------------------------
>> -
>> -A lot of drivers forward gem mmap calls to dma-buf mmap for imported buffers.
>> -And also a lot of them forward dma-buf mmap to the gem mmap implementations.
>> -There's drm_gem_prime_mmap() for this now, but still needs to be rolled out.
>> -
>> -Contact: Daniel Vetter
>> -
>> -Level: Intermediate
>> -
>>   Generic fbdev defio support
>>   ---------------------------
>>   
>> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
>> index 0cd95953cdf5..a84eb4028e5b 100644
>> --- a/include/drm/drm_drv.h
>> +++ b/include/drm/drm_drv.h
>> @@ -345,11 +345,14 @@ struct drm_driver {
>>   	 * mmap hook for GEM drivers, used to implement dma-buf mmap in the
>>   	 * PRIME helpers.
>>   	 *
>> -	 * FIXME: There's way too much duplication going on here, and also moved
>> -	 * to &drm_gem_object_funcs.
>> +	 * This hook only exists for historical reasons. Drivers must use
>> +	 * drm_gem_prime_mmap() to implement it.
>> +	 *
>> +	 * FIXME: Convert all drivers to implement mmap in struct
>> +	 * &drm_gem_object_funcs and inline drm_gem_prime_mmap() into
>> +	 * its callers. This hook should be removed afterwards.
> 
> I think at least i915 has different semantics between dma-buf mmap and gem
> mmap in some cases, so this might be tricky to achieve. But I think
> everywhere else this should be solid.
> -Daniel
> 
>>   	 */
>> -	int (*gem_prime_mmap)(struct drm_gem_object *obj,
>> -				struct vm_area_struct *vma);
>> +	int (*gem_prime_mmap)(struct drm_gem_object *obj, struct vm_area_struct *vma);
>>   
>>   	/**
>>   	 * @dumb_create:
>> -- 
>> 2.33.1
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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