Re: [PATCH 04/10] drm/client: Add drm_client_framebuffer_flush()

Noralf Trønnes
2020-05-03T09:55:01Z

Den 03.05.2020 09.48, skrev Sam Ravnborg:
> Hi Noralf.
>
> On Wed, Apr 29, 2020 at 02:48:24PM +0200, Noralf Trønnes wrote:
>> Some drivers need explicit flushing of buffer changes, add a function
>> that does that.
> I trust you on this.

All drivers in tiny/ and at least udl need to be told to flush changes.
For userspace this happens either by calling DRM_IOCTL_MODE_DIRTYFB or
doing a page/buffer flip DRM_IOCTL_MODE_PAGE_FLIP or do a
DRM_IOCTL_MODE_ATOMIC (can contain damage report using plane property
FB_DAMAGE_CLIPS). For drivers that use drm_gem_fb_create_with_dirty()
and the drm_damage_helper (all of them now I think) this will result in
an atomic commit. The driver can use drm_atomic_helper_damage_merged()
to get the combined damage rectangle.

Noralf.

>
>>
>> Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
> Some bikeshedding below. Either way:
> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
>
>> ---
>> drivers/gpu/drm/drm_client.c | 31 +++++++++++++++++++++++++++++++
>> include/drm/drm_client.h | 1 +
>> 2 files changed, 32 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
>> index cb5ee9f1ffaa..8dbc2ecdcaea 100644
>> --- a/drivers/gpu/drm/drm_client.c
>> +++ b/drivers/gpu/drm/drm_client.c
>> @@ -483,6 +483,37 @@ void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
>> }
>> EXPORT_SYMBOL(drm_client_framebuffer_delete);
>>
>> +/**
>> + * drm_client_framebuffer_flush - Manually flush client framebuffer
>> + * @buffer: DRM client buffer (can be NULL)
>> + * @rect: Damage rectangle (if NULL flushes all)
>> + *
>> + * This calls &drm_framebuffer_funcs->dirty (if present) to flush buffer changes
>> + * for drivers that need it.
>> + *
>> + * Returns:
>> + * Zero on success or negative error code on failure.
>> + */
>
> Alternative proposal - that I think is simpler.
> But both variants works for me.
>> +int drm_client_framebuffer_flush(struct drm_client_buffer *buffer, struct drm_rect *rect)
>> +{
> struct drm_framebuffer_funcs *funcs;
> struct drm_clip_rect clip;
>> +
>> + if (!buffer || !buffer->fb || !buffer->fb->funcs->dirty)
>> + return 0;
> funcs = buffer->fb->funcs;
>> +
>> + if (rect) {
>> + clip.x1 = rect->x1;
>> + clip.y1 = rect->y1;
>> + clip.x2 = rect->x2;
>> + clip.y2 = rect->y2;
> return funcs->dirty(buffer->fb, buffer->client->file,
> 0, 0, &clip, 1);
>> + } else {
> return funcs->dirty(buffer->fb, buffer->client->file,
> 0, 0, NULL, 0);
> }
>
>> +
>> + return buffer->fb->funcs->dirty(buffer->fb, buffer->client->file,
>> + 0, 0, clip, clip ? 1 : 0);
>> +}
>> +EXPORT_SYMBOL(drm_client_framebuffer_flush);
>> +
>> #ifdef CONFIG_DEBUG_FS
>> static int drm_client_debugfs_internal_clients(struct seq_file *m, void *data)
>> {
>> diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
>> index bbb5689fa9a8..6ef5364d6dfb 100644
>> --- a/include/drm/drm_client.h
>> +++ b/include/drm/drm_client.h
>> @@ -156,6 +156,7 @@ struct drm_client_buffer {
>> struct drm_client_buffer *
>> drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format);
>> void drm_client_framebuffer_delete(struct drm_client_buffer *buffer);
>> +int drm_client_framebuffer_flush(struct drm_client_buffer *buffer, struct drm_rect *rect);
>> void *drm_client_buffer_vmap(struct drm_client_buffer *buffer);
>> void drm_client_buffer_vunmap(struct drm_client_buffer *buffer);
>>
>> --
>> 2.23.0
>>
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