linux-kernel - Re: [PATCH 2/6] drm: Add drm_atomic_helper_buffer_damage_{iter

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Message-ID: <8734x872dy.fsf@minerva.mail-host-address-is-not-set>
Date:   Tue, 14 Nov 2023 16:58:33 +0100
From:   Javier Martinez Canillas <javierm@...hat.com>
To:     Thomas Zimmermann <tzimmermann@...e.de>,
        linux-kernel@...r.kernel.org
Cc:     Simon Ser <contact@...rsion.fr>,
        Sima Vetter <daniel.vetter@...ll.ch>,
        Pekka Paalanen <pekka.paalanen@...labora.com>,
        Maxime Ripard <mripard@...nel.org>,
        Bilal Elmoussaoui <belmouss@...hat.com>,
        Erico Nunes <nunes.erico@...il.com>, stable@...r.kernel.org,
        nerdopolis <bluescreen_avenger@...izon.net>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...il.com>,
        Gerd Hoffmann <kraxel@...hat.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 2/6] drm: Add
 drm_atomic_helper_buffer_damage_{iter_init,merged}() helpers

Thomas Zimmermann <tzimmermann@...e.de> writes:

Hello Thomas,

Thanks a lot for your feedback.

> Hi
>
> Am 09.11.23 um 18:24 schrieb Javier Martinez Canillas:
>> To be used by drivers that do per-buffer (e.g: virtio-gpu) uploads (rather
>> than per-plane uploads), since these type of drivers need to handle buffer
>> damages instead of frame damages.
>> 
>> The drm_atomic_helper_buffer_damage_iter_init() has the same logic than
>> drm_atomic_helper_damage_iter_init() but it also takes into account if the
>> framebuffer attached to plane's state has changed since the last update.
>> 
>> And the drm_atomic_helper_buffer_damage_merged() is just a version of the
>> drm_atomic_helper_damage_merged() helper, but it uses the iter_init helper
>> that is mentioned above.
>> 
>> Fixes: 01f05940a9a7 ("drm/virtio: Enable fb damage clips property for the primary plane")
>> Cc: <stable@...r.kernel.org> # v6.4+
>> Reported-by: nerdopolis <bluescreen_avenger@...izon.net>
>> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218115
>> Suggested-by: Sima Vetter <daniel.vetter@...ll.ch>
>> Signed-off-by: Javier Martinez Canillas <javierm@...hat.com>
>> ---
>> 
>>   drivers/gpu/drm/drm_damage_helper.c | 79 ++++++++++++++++++++++++++---
>>   include/drm/drm_damage_helper.h     |  7 +++
>>   2 files changed, 80 insertions(+), 6 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c
>> index aa2325567918..b72062c9d31c 100644
>> --- a/drivers/gpu/drm/drm_damage_helper.c
>> +++ b/drivers/gpu/drm/drm_damage_helper.c
>> @@ -204,7 +204,8 @@ EXPORT_SYMBOL(drm_atomic_helper_dirtyfb);
>>   static void
>>   __drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,
>>   				     const struct drm_plane_state *old_state,
>> -				     const struct drm_plane_state *state)
>> +				     const struct drm_plane_state *state,
>> +				     bool buffer_damage)
>
> I think it would be preferable to drop patches one and two and instead 
> add this parameter directly to drm_atomic_helper_damage_iter_init() and 
> drm_atomic_helper_damage_merged().  That's a bit of churn, but more 
> readable code.
>

Makes sense. I'll do that in v2.

> Best regards
> Thomas
>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat