[PATCH v2 4/8] drm: vkms: Add fb information to `vkms_writeback_job`

Thomas Zimmermann tzimmermann at suse.de
Thu Nov 4 07:21:51 UTC 2021


Hi

Am 03.11.21 um 20:18 schrieb Igor Torrente:
> Hi Thomas,
> 
> On 11/3/21 12:45 PM, Thomas Zimmermann wrote:
>> Hi
>>
>> Am 26.10.21 um 13:34 schrieb Igor Torrente:
>>> This commit is the groundwork to introduce new formats to the planes and
>>> writeback buffer. As part of it, a new buffer metadata field is added to
>>> `vkms_writeback_job`, this metadata is represented by the 
>>> `vkms_composer`
>>> struct.
>>>
>>> This will allow us, in the future, to have different compositing and wb
>>> format types.
>>>
>>> Signed-off-by: Igor Torrente <igormtorrente at gmail.com>
>>> ---
>>> V2: Change the code to get the drm_framebuffer reference and not copy 
>>> its
>>>       contents(Thomas Zimmermann).
>>> ---
>>>    drivers/gpu/drm/vkms/vkms_composer.c  |  4 ++--
>>>    drivers/gpu/drm/vkms/vkms_drv.h       | 12 ++++++------
>>>    drivers/gpu/drm/vkms/vkms_plane.c     | 10 +++++-----
>>>    drivers/gpu/drm/vkms/vkms_writeback.c | 21 ++++++++++++++++++---
>>>    4 files changed, 31 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c 
>>> b/drivers/gpu/drm/vkms/vkms_composer.c
>>> index 82f79e508f81..383ca657ddf7 100644
>>> --- a/drivers/gpu/drm/vkms/vkms_composer.c
>>> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
>>> @@ -153,7 +153,7 @@ static void compose_plane(struct vkms_composer 
>>> *primary_composer,
>>>                  struct vkms_composer *plane_composer,
>>>                  void *vaddr_out)
>>>    {
>>> -    struct drm_framebuffer *fb = &plane_composer->fb;
>>> +    struct drm_framebuffer *fb = plane_composer->fb;
>>>        void *vaddr;
>>>        void (*pixel_blend)(const u8 *p_src, u8 *p_dst);
>>> @@ -174,7 +174,7 @@ static int compose_active_planes(void **vaddr_out,
>>>                     struct vkms_composer *primary_composer,
>>>                     struct vkms_crtc_state *crtc_state)
>>>    {
>>> -    struct drm_framebuffer *fb = &primary_composer->fb;
>>> +    struct drm_framebuffer *fb = primary_composer->fb;
>>>        struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
>>>        const void *vaddr;
>>>        int i;
>>> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h 
>>> b/drivers/gpu/drm/vkms/vkms_drv.h
>>> index 64e62993b06f..9e4c1e95bbb1 100644
>>> --- a/drivers/gpu/drm/vkms/vkms_drv.h
>>> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
>>> @@ -20,13 +20,8 @@
>>>    #define XRES_MAX  8192
>>>    #define YRES_MAX  8192
>>> -struct vkms_writeback_job {
>>> -    struct dma_buf_map map[DRM_FORMAT_MAX_PLANES];
>>> -    struct dma_buf_map data[DRM_FORMAT_MAX_PLANES];
>>> -};
>>> -
>>>    struct vkms_composer {
>>> -    struct drm_framebuffer fb;
>>> +    struct drm_framebuffer *fb;
>>>        struct drm_rect src, dst;
>>>        struct dma_buf_map map[DRM_FORMAT_MAX_PLANES];
>>>        unsigned int offset;
>>> @@ -34,6 +29,11 @@ struct vkms_composer {
>>>        unsigned int cpp;
>>>    };
>>> +struct vkms_writeback_job {
>>> +    struct dma_buf_map data[DRM_FORMAT_MAX_PLANES];
>>> +    struct vkms_composer composer;
>>> +};
>>> +
>>>    /**
>>>     * vkms_plane_state - Driver specific plane state
>>>     * @base: base plane state
>>> diff --git a/drivers/gpu/drm/vkms/vkms_plane.c 
>>> b/drivers/gpu/drm/vkms/vkms_plane.c
>>> index 32409e15244b..0a28cb7a85e2 100644
>>> --- a/drivers/gpu/drm/vkms/vkms_plane.c
>>> +++ b/drivers/gpu/drm/vkms/vkms_plane.c
>>> @@ -50,12 +50,12 @@ static void vkms_plane_destroy_state(struct 
>>> drm_plane *plane,
>>>        struct vkms_plane_state *vkms_state = 
>>> to_vkms_plane_state(old_state);
>>>        struct drm_crtc *crtc = vkms_state->base.base.crtc;
>>> -    if (crtc) {
>>> +    if (crtc && vkms_state->composer->fb) {
>>>            /* dropping the reference we acquired in
>>>             * vkms_primary_plane_update()
>>>             */
>>> -        if (drm_framebuffer_read_refcount(&vkms_state->composer->fb))
>>> -            drm_framebuffer_put(&vkms_state->composer->fb);
>>> +        if (drm_framebuffer_read_refcount(vkms_state->composer->fb))
>>> +            drm_framebuffer_put(vkms_state->composer->fb);
>>>        }
>>>        kfree(vkms_state->composer);
>>> @@ -110,9 +110,9 @@ static void vkms_plane_atomic_update(struct 
>>> drm_plane *plane,
>>>        composer = vkms_plane_state->composer;
>>>        memcpy(&composer->src, &new_state->src, sizeof(struct drm_rect));
>>>        memcpy(&composer->dst, &new_state->dst, sizeof(struct drm_rect));
>>> -    memcpy(&composer->fb, fb, sizeof(struct drm_framebuffer));
>>> +    composer->fb = fb;
>>>        memcpy(&composer->map, &shadow_plane_state->data, 
>>> sizeof(composer->map));
>>> -    drm_framebuffer_get(&composer->fb);
>>> +    drm_framebuffer_get(composer->fb);
>>>        composer->offset = fb->offsets[0];
>>>        composer->pitch = fb->pitches[0];
>>>        composer->cpp = fb->format->cpp[0];
>>> diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c 
>>> b/drivers/gpu/drm/vkms/vkms_writeback.c
>>> index 8694227f555f..32734cdbf6c2 100644
>>> --- a/drivers/gpu/drm/vkms/vkms_writeback.c
>>> +++ b/drivers/gpu/drm/vkms/vkms_writeback.c
>>> @@ -75,12 +75,15 @@ static int vkms_wb_prepare_job(struct 
>>> drm_writeback_connector *wb_connector,
>>>        if (!vkmsjob)
>>>            return -ENOMEM;
>>> -    ret = drm_gem_fb_vmap(job->fb, vkmsjob->map, vkmsjob->data);
>>> +    ret = drm_gem_fb_vmap(job->fb, vkmsjob->composer.map, 
>>> vkmsjob->data);
>>>        if (ret) {
>>>            DRM_ERROR("vmap failed: %d\n", ret);
>>>            goto err_kfree;
>>>        }
>>> +    vkmsjob->composer.fb = job->fb;
>>> +    drm_framebuffer_get(vkmsjob->composer.fb);
>>> +
>>>        job->priv = vkmsjob;
>>>        return 0;
>>> @@ -99,7 +102,10 @@ static void vkms_wb_cleanup_job(struct 
>>> drm_writeback_connector *connector,
>>>        if (!job->fb)
>>>            return;
>>> -    drm_gem_fb_vunmap(job->fb, vkmsjob->map);
>>> +    drm_gem_fb_vunmap(job->fb, vkmsjob->composer.map);
>>> +
>>> +    if (drm_framebuffer_read_refcount(vkmsjob->composer.fb))
>>> +        drm_framebuffer_put(vkmsjob->composer.fb);
>>
>> Why is this protected by an if conditional?
> 
> Here, I followed what was done in the vkms_plane code, just adapting it
> to the writeback callbacks.
> 
> I put this if because I wasn't 100% sure that for each
> `vkms_wb_prepare_job` I would have exactly one `vkms_wb_cleanup_job`
> after it.
> 
> It happened in my testings, but I can't guarantee that it will always
> happen.

It would be strange it it wasn't like that. Sounds like a bug to me. The 
docs say that the cleanup is called for commited and aborted changes. 
TBH, I'd leave out the condition.

Maybe a vkms maintainer can comment on this?

Best regards
Thomas

> 
>>
>> Best regards
>> Thomas
>>
>>>        vkmsdev = drm_device_to_vkms_device(job->fb->dev);
>>>        vkms_set_composer(&vkmsdev->output, false);
>>> @@ -116,14 +122,23 @@ static void vkms_wb_atomic_commit(struct 
>>> drm_connector *conn,
>>>        struct drm_writeback_connector *wb_conn = &output->wb_connector;
>>>        struct drm_connector_state *conn_state = wb_conn->base.state;
>>>        struct vkms_crtc_state *crtc_state = output->composer_state;
>>> +    struct drm_framebuffer *fb = connector_state->writeback_job->fb;
>>> +    struct vkms_writeback_job *active_wb;
>>> +    struct vkms_composer *wb_composer;
>>>        if (!conn_state)
>>>            return;
>>>        vkms_set_composer(&vkmsdev->output, true);
>>> +    active_wb = conn_state->writeback_job->priv;
>>> +    wb_composer = &active_wb->composer;
>>> +
>>>        spin_lock_irq(&output->composer_lock);
>>> -    crtc_state->active_writeback = conn_state->writeback_job->priv;
>>> +    crtc_state->active_writeback = active_wb;
>>> +    wb_composer->offset = fb->offsets[0];
>>> +    wb_composer->pitch = fb->pitches[0];
>>> +    wb_composer->cpp = fb->format->cpp[0];
>>>        crtc_state->wb_pending = true;
>>>        spin_unlock_irq(&output->composer_lock);
>>>        drm_writeback_queue_job(wb_conn, connector_state);
>>>
>>
> 
> Thanks,
> ---
> Igor M. A. Torrente

-- 
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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