On Mon, Jun 17, 2019 at 10:53:46PM -0300, Rodrigo Siqueira wrote:
> Hi Oleg,
>
> First of all, thank you for your patchset.
>
> On 06/13, Daniel Vetter wrote:
> > On Thu, Jun 13, 2019 at 03:18:01PM +0300, Oleg Vasilev wrote:
> > > Because interrupts are generated artifitially, kernel bug may lead to
> > > infinte attempts to submit CRC.
> > >
> > > Signed-off-by: Oleg Vasilev <oleg.vasilev@xxxxxxxxx>
> > > ---
> > > drivers/gpu/drm/vkms/vkms_crc.c | 10 +++++++++-
> > > 1 file changed, 9 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/vkms/vkms_crc.c b/drivers/gpu/drm/vkms/vkms_crc.c
> > > index d7b409a3c0f8..bc717a8888b5 100644
> > > --- a/drivers/gpu/drm/vkms/vkms_crc.c
> > > +++ b/drivers/gpu/drm/vkms/vkms_crc.c
> > > @@ -167,6 +167,7 @@ void vkms_crc_work_handle(struct work_struct *work)
> > > u32 crc32 = 0;
> > > u64 frame_start, frame_end;
> > > unsigned long flags;
> > > + int ret;
> > >
> > > spin_lock_irqsave(&out->state_lock, flags);
> > > frame_start = crtc_state->frame_start;
> > > @@ -202,7 +203,14 @@ void vkms_crc_work_handle(struct work_struct *work)
> > > * missing frames
> > > */
> > > while (frame_start <= frame_end)
> > > - drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
> > > + {
> >
> > Bikeshed: Kernel codingstyle puts this on the same line as the closing )
> > of the while/if/for.
>
> I recommend you to create a post-commit script in your git repo.
> Something like this:
>
> touch .git/hooks/post-commit
>
> In the post-commit, add:
>
> exec git show --format=email HEAD | ./scripts/checkpatch.pl --strict --codespell
>
> > Aside from that not sure that's useful here, we've fixed the bug by now
> > ...
>
> IMHO, this patch is useful because it handles the return value from
> drm_crtc_add_crc_entry() which make the code a little bit more reliable.
> Additionally, it avoids polluting the dmesg output in case of a
> problem.
If it's the return value that annoys you, there's an easy fix: Let's
remove it! None of the other drivers look at it either.
Imo that's clearer than trying to do something reasonable when facing
driver bugs (which this is here).
-Daniel
>
> > -Daniel
> >
> > > + ret = drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
> > > + if (ret) {
> > > + DRM_WARN("VKMS stop generating CRCs\n");
> > > + out->crc_enabled = false;
> > > + break;
> > > + }
> > > + }
> > >
> > > out:
> > > /* to avoid using the same value for frame number again */
> > > --
> > > 2.21.0
> > >
> >
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
>
> --
> Rodrigo Siqueira
> https://siqueira.tech
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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