From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel@ffwll.ch (Daniel Vetter) Date: Fri, 5 Oct 2018 09:58:00 +0200 Subject: [PATCH] drm/meson: fix max mode_config height/width In-Reply-To: <8e980de4-5a52-8f3d-fba2-734617e40d1b@baylibre.com> References: <1538642563-22465-1-git-send-email-narmstrong@baylibre.com> <20181004100958.GI31561@phenom.ffwll.local> <0ef7fa13-ce77-f8a5-f5f3-6568be3d6145@baylibre.com> <8e980de4-5a52-8f3d-fba2-734617e40d1b@baylibre.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Oct 5, 2018 at 9:39 AM Neil Armstrong wrote: > > On 04/10/2018 20:10, Daniel Vetter wrote: > > On Thu, Oct 4, 2018 at 5:05 PM Neil Armstrong wrote: > >> > >> On 04/10/2018 12:09, Daniel Vetter wrote: > >>> On Thu, Oct 04, 2018 at 10:42:43AM +0200, Neil Armstrong wrote: > >>>> The mode_config max_width/max_height determines the maximum framebuffer > >>>> size the pixel reader can handle. But the values were set thinking they > >>>> were determining the maximum screen dimensions. > >>>> > >>>> This patch changes the values to the maximum height/width the CANVAS block > >>>> can handle rounded to some coherent values. > >>>> > >>>> Fixes: a41e82e6c457 ("drm/meson: Add support for components") > >>>> Signed-off-by: Neil Armstrong > >>> > >>> It's both. Grep for all the callers of ->fill_modes and you'll see that > >>> this limit is also used to filter max screen sizes. > >>> > >>> If you want to change this, then I think we need a new > >>> mode_config.fb_max_width/height, which if non-zero, would extend the limit > >>> for fbs. > >>> > >>> There's also the problem that if you extend this for fbs, then there's no > >>> check anymore in the atomic_commit paths (or legacy modeset), so that > >>> needs to be addressed somehow too. > >> > >> What about adding optionals mode_config.fb_max_width/height and update > >> drm_internal_framebuffer_create() to use these if non-0 or fallback > >> to the mode_config max_width/max_height. > > > > That's what I meant. Except you also need to then fix the gap you've > > opened in atomic_check, and validate the mode size against > > mode_config.max_width/height. > > OK, won't this be enough ? > --- a/include/drm/drm_mode_config.h > +++ b/include/drm/drm_mode_config.h > @@ -333,6 +333,8 @@ struct drm_mode_config_funcs { > * @min_height: minimum fb pixel height on this device > * @max_width: maximum fb pixel width on this device > * @max_height: maximum fb pixel height on this device > + * @max_fb_width: maximum fb buffer width if differs from max_width > + * @max_fb_height: maximum fb buffer height if differs from max_height > * @funcs: core driver provided mode setting functions > * @fb_base: base address of the framebuffer > * @poll_enabled: track polling support for this device > @@ -508,6 +510,7 @@ struct drm_mode_config { > > int min_width, min_height; > int max_width, max_height; > + int max_fb_width, max_fb_height; > const struct drm_mode_config_funcs *funcs; > resource_size_t fb_base; > > --- a/drivers/gpu/drm/drm_framebuffer.c > +++ b/drivers/gpu/drm/drm_framebuffer.c > @@ -283,14 +283,20 @@ drm_internal_framebuffer_create(struct drm_device *dev, > return ERR_PTR(-EINVAL); > } > > - if ((config->min_width > r->width) || (r->width > config->max_width)) { > + if ((config->min_width > r->width) || > + (!config->max_fb_width && r->width > config->max_width) || > + (config->max_fb_width && r->width > config->max_fb_width)) { > DRM_DEBUG_KMS("bad framebuffer width %d, should be >= %d && <= %d\n", > - r->width, config->min_width, config->max_width); > + r->width, config->min_width, config->max_fb_width ? > + config->max_fb_width : config->max_width); > return ERR_PTR(-EINVAL); > } > - if ((config->min_height > r->height) || (r->height > config->max_height)) { > + if ((config->min_height > r->height) || > + (!config->max_fb_height && r->height > config->max_height) || > + (config->max_fb_height && r->height > config->max_fb_height)) { > DRM_DEBUG_KMS("bad framebuffer height %d, should be >= %d && <= %d\n", > - r->height, config->min_height, config->max_height); > + r->height, config->min_height, config->max_fb_height ? > + config->max_fb_height : config->max_height); > return ERR_PTR(-EINVAL); > } > > and in the driver : > > + drm->mode_config.max_width = 4096; > + drm->mode_config.max_height = 3840; > + drm->mode_config.max_fb_width = 16384; > + drm->mode_config.max_fb_height = 8192; > > With this I leave the mode filtering intact. Not enough. See https://dri.freedesktop.org/docs/drm/gpu/drm-kms-helpers.html#c.drm_connector_helper_funcs and scroll down to mode_valid. You need to filter modes both in the detect paths, and the atomic_check paths. Detect is explicitly filtered out, but atomic_check was only implicitly filtered, through the max fb size checks. Ok, you could light up a mode that's bigger than max fb, but in practice, no userspace ever did that. But with your code we're missing crucial validation now, and userspace could fall over that. What I think we need is to add mode filter against mode_config.max_width/height in drm_atomic_helper_check_modeset(). Probably best to stuff that into the mode_valid() function. Cheers, Daniel > > Neil > > > > -Daniel > > > >> > >> Neil > >> > >>> > >>> Bunch of igt to make sure we're not missing anything would be sweet on > >>> top, e.g. e.g. trying to set a mode over the limit and making sure it > >>> fails. > >>> > >>> Cheers, Daniel > >>> > >>>> --- > >>>> drivers/gpu/drm/meson/meson_drv.c | 4 ++-- > >>>> 1 file changed, 2 insertions(+), 2 deletions(-) > >>>> > >>>> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c > >>>> index d344312..2e29968 100644 > >>>> --- a/drivers/gpu/drm/meson/meson_drv.c > >>>> +++ b/drivers/gpu/drm/meson/meson_drv.c > >>>> @@ -243,8 +243,8 @@ static int meson_drv_bind_master(struct device *dev, bool has_components) > >>>> goto free_drm; > >>>> > >>>> drm_mode_config_init(drm); > >>>> - drm->mode_config.max_width = 3840; > >>>> - drm->mode_config.max_height = 2160; > >>>> + drm->mode_config.max_width = 16384; > >>>> + drm->mode_config.max_height = 8192; > >>>> drm->mode_config.funcs = &meson_mode_config_funcs; > >>>> > >>>> /* Hardware Initialization */ > >>>> -- > >>>> 2.7.4 > >>>> > >>>> _______________________________________________ > >>>> dri-devel mailing list > >>>> dri-devel at lists.freedesktop.org > >>>> https://lists.freedesktop.org/mailman/listinfo/dri-devel > >>> > >> > >> _______________________________________________ > >> dri-devel mailing list > >> dri-devel at lists.freedesktop.org > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > > > > -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch