| Message ID | 20230704160133.20261-5-tzimmermann@suse.de |
|---|---|
| State | New |
| Headers | show |
| Series | drm: Improve fbdev emulation for DMA-able framebuffers | expand |
Thomas Zimmermann <tzimmermann@suse.de> writes: > Set fbdev default flags FBNFO_DEFAULT and mark the framebuffer with > FBINFO_VIRTFB. The framebuffer range is in DMA-able memory and should > be accessed with the CPU's regular memory ops. > > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> > Cc: Thierry Reding <thierry.reding@gmail.com> > Cc: Mikko Perttunen <mperttunen@nvidia.com> > --- > drivers/gpu/drm/tegra/fbdev.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/tegra/fbdev.c b/drivers/gpu/drm/tegra/fbdev.c > index 82577b7c88da..8074430c52f1 100644 > --- a/drivers/gpu/drm/tegra/fbdev.c > +++ b/drivers/gpu/drm/tegra/fbdev.c > @@ -103,6 +103,8 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper, > return PTR_ERR(info); > } > > + info->flags = FBINFO_DEFAULT; > + > fb = tegra_fb_alloc(drm, &cmd, &bo, 1); > if (IS_ERR(fb)) { > err = PTR_ERR(fb); > @@ -132,6 +134,7 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper, > } > } > > + info->flags |= FBINFO_VIRTFB; I see that all fbdev drivers just do: info->flags = FBINFO_FLAG_DEFAULT | FBINFO_VIRTFB Guess you are doing in two assignments to be consistent with drm_fbdev_dma.c ? I was just curious about the rationale for setting the flags in two steps. Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Hi Am 05.07.23 um 11:34 schrieb Javier Martinez Canillas: > Thomas Zimmermann <tzimmermann@suse.de> writes: > > [...] > >>>> + info->flags |= FBINFO_VIRTFB; >>> >>> I see that all fbdev drivers just do: info->flags = FBINFO_FLAG_DEFAULT | FBINFO_VIRTFB >>> >>> Guess you are doing in two assignments to be consistent with drm_fbdev_dma.c ? >>> I was just curious about the rationale for setting the flags in two steps. >> >> The _DEFAULT flag is really just a zero. And the other flags describe >> different aspects of the framebuffer. I think it makes sense to set the >> flags together with the respective state. For example, _VIRTFB is set >> next to ->screen_buffer, because they belong together. >> > > Yes, that makes sense. > >> _VIRTFB is currently only used in defio code at >> >> https://elixir.bootlin.com/linux/latest/source/drivers/video/fbdev/core/fb_defio.c#L232 >> >> I think the fbdev I/O helpers should also test this flag after all >> drivers have been annotated correctly. For example, fb_io_read() would >> WARN_ONCE if the _VIRTFB flag has been set; and fb_sys_read() would warn >> if it hasn't been set. For the read helpers, it also makes sense to >> WARN_ONCE if the _READS_FAST flag has not been set. >> > > Agreed. Maybe you could add those warn (or at least info or debug?) even > if not all drivers have been annotated correctly. That way people can be > aware that is missing and fix if there are remaining drivers. Yes, we could do that. I want to go through drivers first and fix the low-hanging fruits. Some of the old fbdev drivers use either DMA or I/O memory. They would only be fix-worthy if someone complains. Best regards Thomas > >> Best regards >> Thomas >> >
diff --git a/drivers/gpu/drm/tegra/fbdev.c b/drivers/gpu/drm/tegra/fbdev.c index 82577b7c88da..8074430c52f1 100644 --- a/drivers/gpu/drm/tegra/fbdev.c +++ b/drivers/gpu/drm/tegra/fbdev.c @@ -103,6 +103,8 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper, return PTR_ERR(info); } + info->flags = FBINFO_DEFAULT; + fb = tegra_fb_alloc(drm, &cmd, &bo, 1); if (IS_ERR(fb)) { err = PTR_ERR(fb); @@ -132,6 +134,7 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper, } } + info->flags |= FBINFO_VIRTFB; info->screen_base = (void __iomem *)bo->vaddr + offset; info->screen_size = size; info->fix.smem_start = (unsigned long)(bo->iova + offset);
Set fbdev default flags FBNFO_DEFAULT and mark the framebuffer with FBINFO_VIRTFB. The framebuffer range is in DMA-able memory and should be accessed with the CPU's regular memory ops. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Mikko Perttunen <mperttunen@nvidia.com> --- drivers/gpu/drm/tegra/fbdev.c | 3 +++ 1 file changed, 3 insertions(+)