On Tue, Sep 08, 2020 at 02:29:02PM +0200, Daniel Vetter wrote: > On Tue, Sep 8, 2020 at 2:07 PM Stefan Agner <ste...@agner.ch> wrote: > > On 2020-09-08 10:48, Daniel Vetter wrote: > >> On Tue, Sep 08, 2020 at 11:18:25AM +0300, Tomi Valkeinen wrote: > >>> On 08/09/2020 10:55, Stefan Agner wrote: > >>>> On 2020-09-07 20:18, Daniel Vetter wrote: > >>>>> On Mon, Sep 07, 2020 at 07:17:12PM +0300, Laurent Pinchart wrote: > >>>>>> Hi Stefan, > >>>>>> > >>>>>> Thank you for the patch. > >>>>>> > >>>>>> On Mon, Sep 07, 2020 at 06:03:43PM +0200, Stefan Agner wrote: > >>>>>>> The lcdif IP does not support a framebuffer pitch (stride) other than > >>>>>>> the CRTC width. Check for equality and reject the state otherwise. > >>>>>>> > >>>>>>> This prevents a distorted picture when using 640x800 and running the > >>>>>>> Mesa graphics stack. Mesa tires to use a cache aligned stride, which > >>>>>> > >>>>>> 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. > >>>>>> > >>>>>> I'm increasingly impressed by how featureful this IP core is :-) > >>>>>> > >>>>>>> Signed-off-by: Stefan Agner <ste...@agner.ch> > >>>>>>> --- > >>>>>>> drivers/gpu/drm/mxsfb/mxsfb_kms.c | 22 ++++++++++++++++++---- > >>>>>>> 1 file changed, 18 insertions(+), 4 deletions(-) > >>>>>>> > >>>>>>> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c > >>>>>>> b/drivers/gpu/drm/mxsfb/mxsfb_kms.c > >>>>>>> index b721b8b262ce..79aa14027f91 100644 > >>>>>>> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c > >>>>>>> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c > >>>>>>> @@ -403,14 +403,28 @@ static int mxsfb_plane_atomic_check(struct > >>>>>>> drm_plane *plane, > >>>>>>> { > >>>>>>> struct mxsfb_drm_private *mxsfb = > >>>>>>> to_mxsfb_drm_private(plane->dev); > >>>>>>> struct drm_crtc_state *crtc_state; > >>>>>>> + unsigned int pitch; > >>>>>>> + int ret; > >>>>>>> > >>>>>>> crtc_state = drm_atomic_get_new_crtc_state(plane_state->state, > >>>>>>> &mxsfb->crtc); > >>>>>>> > >>>>>>> - return drm_atomic_helper_check_plane_state(plane_state, > >>>>>>> crtc_state, > >>>>>>> - > >>>>>>> DRM_PLANE_HELPER_NO_SCALING, > >>>>>>> - > >>>>>>> DRM_PLANE_HELPER_NO_SCALING, > >>>>>>> - false, true); > >>>>>>> + ret = drm_atomic_helper_check_plane_state(plane_state, > >>>>>>> crtc_state, > >>>>>>> + > >>>>>>> DRM_PLANE_HELPER_NO_SCALING, > >>>>>>> + > >>>>>>> DRM_PLANE_HELPER_NO_SCALING, > >>>>>>> + false, true); > >>>>>>> + if (ret || !plane_state->visible) > >>>>>> > >>>>>> Would it be more explict to check for !plane_state->fb ? Otherwise I'll > >>>>>> have to verify that !fb always implies !visible :-) > >>>>>> > >>>>>>> + return ret; > >>>>>>> + > >>>>>>> + pitch = crtc_state->mode.hdisplay * > >>>>>>> + plane_state->fb->format->cpp[0]; > >>>>>> > >>>>>> This holds on a single line. > >>>>>> > >>>>>>> + if (plane_state->fb->pitches[0] != pitch) { > >>>>>>> + dev_err(plane->dev->dev, > >>>>>>> + "Invalid pitch: fb and crtc widths must be > >>>>>>> the same"); > >>>>>> > >>>>>> I'd turn this into a dev_dbg(), printing error messages to the kernel > >>>>>> log in response to user-triggered conditions is a bit too verbose and > >>>>>> could flood the log. > >>>>>> > >>>>>> Wouldn't it be best to catch this issue when creating the framebuffer ? > >>>>> > >>>>> Yeah this should be verified at addfb time. We try to validate as early > >>>>> as > >>>>> possible. > >>>>> -Daniel > >>>>> > >>>> > >>>> Sounds sensible. From what I can tell fb_create is the proper callback > >>>> to implement this at addfb time. Will give this a try. > >>>> > >>>> FWIW, I got the idea from drivers/gpu/drm/tilcdc/tilcdc_plane.c. Maybe > >>>> should be moved to addfb there too? > >>> > >>> But you don't know the crtc width when creating the framebuffer. > >> > >> Hm right this is a different check. What we could check in fb_create for > >> both is that the logical fb size matches exactly the pitch. That's not > >> sufficient criteria, but it will at least catch some of them already. > >> > >> But yeah we'd need both here. > > > > After validating width of framebuffer against pitch, the only thing we > > need to check here is that the width matches. From what I can tell, > > least for mxsfb, this should be covered by > > drm_atomic_helper_check_plane_state's can_position parameter set to > > false. > > This only checks against the src rectangle of the crtc state, there's > nothing forcing that the size of the fb matches the src rectangle > exactly. I guess we could maybe add that as another parameter for hw > like yours or tilcdc. Naming is a bit tricky, maybe > require_matching_fb or src_must_match_fb or something like that.
Can we turn those parameters into flags ? false, true, false is hard to read. > > So I think in my case I can get away by only checking the framebuffer. > > You still need both I think. -- Regards, Laurent Pinchart _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel