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From: Alex Deucher <alexdeucher@gmail.com>
To: "Christian König" <christian.koenig@amd.com>,
	"Zhenneng Li" <lizhenneng@kylinos.cn>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Pan, Xinhui" <Xinhui.Pan@amd.com>,
	"David Airlie" <airlied@linux.ie>,
	"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
	"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
	LKML <linux-kernel@vger.kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH] drm/radeon: Update pitch for page flip
Date: Mon, 2 Aug 2021 10:51:51 -0400	[thread overview]
Message-ID: <CADnq5_PDtEn1y5HJBRHXw8o11LVwSRDKNtQgZtN5u0CW5ZspnQ@mail.gmail.com> (raw)
In-Reply-To: <YQetXMaASz/F2EyS@phenom.ffwll.local>

On Mon, Aug 2, 2021 at 4:31 AM Daniel Vetter <daniel@ffwll.ch> wrote:
>
> On Mon, Aug 02, 2021 at 10:12:47AM +0200, Christian König wrote:
> > Am 02.08.21 um 09:43 schrieb Zhenneng Li:
> > > When primary bo is updated, crtc's pitch may
> > > have not been updated, this will lead to show
> > > disorder content when user changes display mode,
> > > we update crtc's pitch in page flip to avoid
> > > this bug.
> > > This refers to amdgpu's pageflip.
> >
> > Alex is the expert to ask about that code, but I'm not sure if that is
> > really correct for the old hardware.
> >
> > As far as I know the crtc's pitch should not change during a page flip, but
> > only during a full mode set.
> >
> > So could you elaborate a bit more how you trigger this?
>
> legacy page_flip ioctl only verifies that the fb->format stays the same.
> It doesn't check anything else (afair never has), this is all up to
> drivers to verify.
>
> Personally I'd say add a check to reject this, since testing this and
> making sure it really works everywhere is probably a bit much on this old
> hw.

If just the pitch changed, that probably wouldn't be much of a
problem, but if the pitch is changing, that probably implies other
stuff has changed as well and we'll just be chasing changes.  I agree
it would be best to just reject anything other than updating the
scanout address.

Alex

> -Daniel
>
> >
> > Thanks,
> > Christian.
> >
> > >
> > > Cc: Alex Deucher <alexander.deucher@amd.com>
> > > Cc: "Christian König" <christian.koenig@amd.com>
> > > Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
> > > Cc: David Airlie <airlied@linux.ie>
> > > Cc: Daniel Vetter <daniel@ffwll.ch>
> > > Cc: amd-gfx@lists.freedesktop.org
> > > Cc: dri-devel@lists.freedesktop.org
> > > Cc: linux-kernel@vger.kernel.org
> > > Signed-off-by: Zhenneng Li <lizhenneng@kylinos.cn>
> > > ---
> > >   drivers/gpu/drm/radeon/evergreen.c | 8 +++++++-
> > >   1 file changed, 7 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
> > > index 36a888e1b179..eeb590d2dec2 100644
> > > --- a/drivers/gpu/drm/radeon/evergreen.c
> > > +++ b/drivers/gpu/drm/radeon/evergreen.c
> > > @@ -28,6 +28,7 @@
> > >   #include <drm/drm_vblank.h>
> > >   #include <drm/radeon_drm.h>
> > > +#include <drm/drm_fourcc.h>
> > >   #include "atom.h"
> > >   #include "avivod.h"
> > > @@ -1414,10 +1415,15 @@ void evergreen_page_flip(struct radeon_device *rdev, int crtc_id, u64 crtc_base,
> > >                      bool async)
> > >   {
> > >     struct radeon_crtc *radeon_crtc = rdev->mode_info.crtcs[crtc_id];
> > > +   struct drm_framebuffer *fb = radeon_crtc->base.primary->fb;
> > > -   /* update the scanout addresses */
> > > +   /* flip at hsync for async, default is vsync */
> > >     WREG32(EVERGREEN_GRPH_FLIP_CONTROL + radeon_crtc->crtc_offset,
> > >            async ? EVERGREEN_GRPH_SURFACE_UPDATE_H_RETRACE_EN : 0);
> > > +   /* update pitch */
> > > +   WREG32(EVERGREEN_GRPH_PITCH + radeon_crtc->crtc_offset,
> > > +          fb->pitches[0] / fb->format->cpp[0]);
> > > +   /* update the scanout addresses */
> > >     WREG32(EVERGREEN_GRPH_PRIMARY_SURFACE_ADDRESS_HIGH + radeon_crtc->crtc_offset,
> > >            upper_32_bits(crtc_base));
> > >     WREG32(EVERGREEN_GRPH_PRIMARY_SURFACE_ADDRESS + radeon_crtc->crtc_offset,
> > >
> > > No virus found
> > >             Checked by Hillstone Network AntiVirus
> >
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

  reply	other threads:[~2021-08-02 14:52 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02  7:43 Zhenneng Li
     [not found] ` <e6e77cfb-4e6b-c30e-ae7c-ac84b82c9a75@amd.com>
2021-08-02  8:31   ` Daniel Vetter
2021-08-02 14:51     ` Alex Deucher [this message]
2021-08-03  8:00       ` 李真能
2021-08-03  8:34       ` Michel Dänzer
2021-08-03 14:49         ` Alex Deucher
2021-08-04 15:46           ` Daniel Vetter

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