drm/modes: Skip invalid cmdline mode

The named mode could be invalid and then cmdline parser misses to validate
mode's dimensions, happily adding 0x0 mode as a valid mode. One case where
this happens is NVIDIA Tegra devices that are using downstream bootloader
which adds "video=tegrafb" to the kernel's cmdline and thus upstream Tegra
DRM driver fails to probe because of the invalid mode.

Fixes: 555697d726f0 ("drm/modes: Support modes names on the command line")
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190709145151.23086-1-digetx@gmail.com

diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
index e95fceac8f8bf38d3f837b636cd05bf0e41d2cac..56d36779d21321f0e4c74d1606b6952bdee392a9 100644 (file)
--- a/drivers/gpu/drm/drm_client_modeset.c
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -180,7 +180,8 @@ again:
 
 create_mode:
        mode = drm_mode_create_from_cmdline_mode(connector->dev, cmdline_mode);
-       list_add(&mode->head, &connector->modes);
+       if (mode)
+               list_add(&mode->head, &connector->modes);
 
        return mode;
 }

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 910561d4f07196a0297d44542400f08307758792..74a5739df506aaed0994f842e024f55fec4ea4aa 100644 (file)
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -158,6 +158,9 @@ struct drm_display_mode *drm_cvt_mode(struct drm_device *dev, int hdisplay,
        int interlace;
        u64 tmp;
 
+       if (!hdisplay || !vdisplay)
+               return NULL;
+
        /* allocate the drm_display_mode structure. If failure, we will
         * return directly
         */
@@ -392,6 +395,9 @@ drm_gtf_mode_complex(struct drm_device *dev, int hdisplay, int vdisplay,
        int hsync, hfront_porch, vodd_front_porch_lines;
        unsigned int tmp1, tmp2;
 
+       if (!hdisplay || !vdisplay)
+               return NULL;
+
        drm_mode = drm_mode_create(dev);
        if (!drm_mode)
                return NULL;