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SubjectRe: [PATCH v1] drm/modes: Skip invalid cmdline mode
On Tue, Jul 09, 2019 at 05:51:51PM +0300, Dmitry Osipenko wrote:
> 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: 3aeeb13d8996 ("drm/modes: Support modes names on the command line")

Is that actually true? This problem has been in the code since forever AFAICS.

> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/gpu/drm/drm_client_modeset.c | 3 ++-
> drivers/gpu/drm/drm_modes.c | 6 ++++++
> 2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
> index e95fceac8f8b..56d36779d213 100644
> --- a/drivers/gpu/drm/drm_client_modeset.c
> +++ b/drivers/gpu/drm/drm_client_modeset.c
> @@ -180,7 +180,8 @@ drm_connector_pick_cmdline_mode(struct drm_connector *connector)
>
> 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);

That's the same as what I did here
https://patchwork.freedesktop.org/patch/309223/?series=61781&rev=1

But I'd have to rebase that so let's just go with your patch.

>
> return mode;
> }
> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> index 910561d4f071..74a5739df506 100644
> --- 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;
> +

These lgtm

Patch is
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> drm_mode = drm_mode_create(dev);
> if (!drm_mode)
> return NULL;
> --
> 2.22.0
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

--
Ville Syrjälä
Intel

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