linux-kernel - Re: [PATCH v5 1/3] drm/vkms: Decouple crc operations from composer

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Message-ID: <CAJeY4oFtusegHafy8oSYE2Z3T8YCYE6TdMiOHr9gnxV8B=9V8w@mail.gmail.com>
Date:   Tue, 25 Aug 2020 13:12:12 -0300
From:   Melissa Wen <melissa.srw@...il.com>
To:     Rodrigo Siqueira <rodrigosiqueiramelo@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        Brian Starkey <brian.starkey@....com>,
        Liviu Dudau <liviu.dudau@....com>,
        Daniel Vetter <daniel@...ll.ch>,
        Simon Ser <contact@...rsion.fr>,
        Leandro Ribeiro <leandro.ribeiro@...labora.com>,
        daniels@...labora.com, Emil Velikov <emil.l.velikov@...il.com>
Subject: Re: [PATCH v5 1/3] drm/vkms: Decouple crc operations from composer

On Mon, Aug 24, 2020 at 11:31 PM Rodrigo Siqueira
<rodrigosiqueiramelo@...il.com> wrote:
>
> In the vkms_composer.c, some of the functions related to CRC and compose
> have interdependence between each other. This patch reworks some
> functions inside vkms_composer to make crc and composer computation
> decoupled.
>
> This patch is preparation work for making vkms able to support new
> features.
>
> Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@...il.com>
> ---
>  drivers/gpu/drm/vkms/vkms_composer.c | 49 ++++++++++++++++------------
>  1 file changed, 29 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
> index 4f3b07a32b60..4d8bc04bb6ee 100644
> --- a/drivers/gpu/drm/vkms/vkms_composer.c
> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> @@ -108,35 +108,31 @@ static void compose_cursor(struct vkms_composer *cursor_composer,
>               primary_composer, cursor_composer);
>  }
>
> -static uint32_t _vkms_get_crc(struct vkms_composer *primary_composer,
> -                             struct vkms_composer *cursor_composer)
> +static int compose_planes(void **vaddr_out,
> +                         struct vkms_composer *primary_composer,
> +                         struct vkms_composer *cursor_composer)
>  {
>         struct drm_framebuffer *fb = &primary_composer->fb;
>         struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
>         struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(gem_obj);
> -       void *vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
> -       u32 crc = 0;
>
> -       if (!vaddr_out) {
> -               DRM_ERROR("Failed to allocate memory for output frame.");
> -               return 0;
> +       if (!*vaddr_out) {
> +               *vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
> +               if (!*vaddr_out) {
> +                       DRM_ERROR("Cannot allocate memory for output frame.");
> +                       return -ENOMEM;
> +               }
>         }
>
> -       if (WARN_ON(!vkms_obj->vaddr)) {
> -               kfree(vaddr_out);
> -               return crc;
> -       }
> +       if (WARN_ON(!vkms_obj->vaddr))
> +               return -EINVAL;
>
> -       memcpy(vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
> +       memcpy(*vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
>
>         if (cursor_composer)
> -               compose_cursor(cursor_composer, primary_composer, vaddr_out);
> +               compose_cursor(cursor_composer, primary_composer, *vaddr_out);
>
> -       crc = compute_crc(vaddr_out, primary_composer);
> -
> -       kfree(vaddr_out);
> -
> -       return crc;
> +       return 0;
>  }
>
>  /**
> @@ -157,9 +153,11 @@ void vkms_composer_worker(struct work_struct *work)
>         struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
>         struct vkms_composer *primary_composer = NULL;
>         struct vkms_composer *cursor_composer = NULL;
> +       void *vaddr_out = NULL;
>         u32 crc32 = 0;
>         u64 frame_start, frame_end;
>         bool crc_pending;
> +       int ret;
>
>         spin_lock_irq(&out->composer_lock);
>         frame_start = crtc_state->frame_start;
> @@ -183,14 +181,25 @@ void vkms_composer_worker(struct work_struct *work)
>         if (crtc_state->num_active_planes == 2)
>                 cursor_composer = crtc_state->active_planes[1]->composer;
>
> -       if (primary_composer)
> -               crc32 = _vkms_get_crc(primary_composer, cursor_composer);
> +       if (!primary_composer)
> +               return;
> +
> +       ret = compose_planes(&vaddr_out, primary_composer, cursor_composer);
> +       if (ret) {
> +               if (ret == -EINVAL)
> +                       kfree(vaddr_out);
> +               return;
> +       }
> +
> +       crc32 = compute_crc(vaddr_out, primary_composer);
>
>         /*
>          * The worker can fall behind the vblank hrtimer, make sure we catch up.
>          */
>         while (frame_start <= frame_end)
>                 drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
> +
> +       kfree(vaddr_out);
>  }
>
>  static const char * const pipe_crc_sources[] = {"auto"};
> --
> 2.28.0
>

Tested-by: Melissa Wen <melissa.srw@...il.com>