| Message ID | 20200908125558.256843-1-stefan@agner.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm: mxsfb: check framebuffer pitch | expand |
Hi Stefan, Thank you for the patch. On Tue, Sep 08, 2020 at 02:55:58PM +0200, Stefan Agner wrote: > The lcdif IP does not support a framebuffer pitch (stride) other than > framebuffer width. Check for equality and reject the framebuffer > otherwise. > > This prevents a distorted picture when using 640x800 and running the > Mesa graphics stack. Mesa tires to use a cache aligned stride, which Still s/tires/tries/ :-) > leads at that particular resolution to width != stride. Currently > Mesa has no fallback behavior, but rejecting this configuration allows > userspace to handle the issue correctly. > > Signed-off-by: Stefan Agner <stefan@agner.ch> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > --- > drivers/gpu/drm/mxsfb/mxsfb_drv.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c > index 8c549c3931af..fa6798d21029 100644 > --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c > +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c > @@ -21,6 +21,7 @@ > #include <drm/drm_connector.h> > #include <drm/drm_drv.h> > #include <drm/drm_fb_helper.h> > +#include <drm/drm_fourcc.h> > #include <drm/drm_gem_cma_helper.h> > #include <drm/drm_gem_framebuffer_helper.h> > #include <drm/drm_irq.h> > @@ -81,8 +82,26 @@ void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb) > clk_disable_unprepare(mxsfb->clk_axi); > } > > +static struct drm_framebuffer * > +mxsfb_fb_create(struct drm_device *dev, struct drm_file *file_priv, > + const struct drm_mode_fb_cmd2 *mode_cmd) > +{ > + const struct drm_format_info *info; > + > + info = drm_get_format_info(dev, mode_cmd); > + if (!info) > + return ERR_PTR(-EINVAL); > + > + if (mode_cmd->width * info->cpp[0] != mode_cmd->pitches[0]) { > + dev_dbg(dev->dev, "Invalid pitch: fb width must match pitch\n"); > + return ERR_PTR(-EINVAL); > + } > + > + return drm_gem_fb_create(dev, file_priv, mode_cmd); > +} > + > static const struct drm_mode_config_funcs mxsfb_mode_config_funcs = { > - .fb_create = drm_gem_fb_create, > + .fb_create = mxsfb_fb_create, > .atomic_check = drm_atomic_helper_check, > .atomic_commit = drm_atomic_helper_commit, > };
Hi Stefan, On Tue, Sep 8, 2020 at 9:56 AM Stefan Agner <stefan@agner.ch> wrote: > > The lcdif IP does not support a framebuffer pitch (stride) other than > framebuffer width. Check for equality and reject the framebuffer > otherwise. > > This prevents a distorted picture when using 640x800 and running the > Mesa graphics stack. Mesa tires to use a cache aligned stride, which > leads at that particular resolution to width != stride. Currently > Mesa has no fallback behavior, but rejecting this configuration allows > userspace to handle the issue correctly. What about adding a Fixes tag so that it can be backported to old stable kernels? Thanks
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c index 8c549c3931af..fa6798d21029 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c @@ -21,6 +21,7 @@ #include <drm/drm_connector.h> #include <drm/drm_drv.h> #include <drm/drm_fb_helper.h> +#include <drm/drm_fourcc.h> #include <drm/drm_gem_cma_helper.h> #include <drm/drm_gem_framebuffer_helper.h> #include <drm/drm_irq.h> @@ -81,8 +82,26 @@ void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb) clk_disable_unprepare(mxsfb->clk_axi); } +static struct drm_framebuffer * +mxsfb_fb_create(struct drm_device *dev, struct drm_file *file_priv, + const struct drm_mode_fb_cmd2 *mode_cmd) +{ + const struct drm_format_info *info; + + info = drm_get_format_info(dev, mode_cmd); + if (!info) + return ERR_PTR(-EINVAL); + + if (mode_cmd->width * info->cpp[0] != mode_cmd->pitches[0]) { + dev_dbg(dev->dev, "Invalid pitch: fb width must match pitch\n"); + return ERR_PTR(-EINVAL); + } + + return drm_gem_fb_create(dev, file_priv, mode_cmd); +} + static const struct drm_mode_config_funcs mxsfb_mode_config_funcs = { - .fb_create = drm_gem_fb_create, + .fb_create = mxsfb_fb_create, .atomic_check = drm_atomic_helper_check, .atomic_commit = drm_atomic_helper_commit, };
The lcdif IP does not support a framebuffer pitch (stride) other than framebuffer width. Check for equality and reject the framebuffer otherwise. This prevents a distorted picture when using 640x800 and running the Mesa graphics stack. Mesa tires to use a cache aligned stride, which leads at that particular resolution to width != stride. Currently Mesa has no fallback behavior, but rejecting this configuration allows userspace to handle the issue correctly. Signed-off-by: Stefan Agner <stefan@agner.ch> --- drivers/gpu/drm/mxsfb/mxsfb_drv.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-)