[PATCH] video: hyperv_fb: Fix hibernation for the deferred IO feature

[Wei Hu]

> -----Original Message-----
> From: Wei Hu
> Sent: 2019年11月21日 10:47
> To: Dexuan Cui <decui at microsoft.com>; KY Srinivasan <kys at microsoft.com>;
> Haiyang Zhang <haiyangz at microsoft.com>; Stephen Hemminger
> <sthemmin at microsoft.com>; sashal at kernel.org; b.zolnierkie at samsung.com;
> linux-hyperv at vger.kernel.org; dri-devel at lists.freedesktop.org; linux-
> fbdev at vger.kernel.org; linux-kernel at vger.kernel.org; Michael Kelley
> <mikelley at microsoft.com>; Sasha Levin <Alexander.Levin at microsoft.com>
> Subject: RE: [PATCH] video: hyperv_fb: Fix hibernation for the deferred IO
> feature
> 
> > -----Original Message-----
> > From: Dexuan Cui <decui at microsoft.com>
> > Sent: Wednesday, November 20, 2019 3:14 PM
> > To: KY Srinivasan <kys at microsoft.com>; Haiyang Zhang
> > <haiyangz at microsoft.com>; Stephen Hemminger
> <sthemmin at microsoft.com>;
> > sashal at kernel.org; b.zolnierkie at samsung.com; linux-hyperv at vger.kernel.org;
> > dri-devel at lists.freedesktop.org; linux-fbdev at vger.kernel.org; linux-
> > kernel at vger.kernel.org; Michael Kelley <mikelley at microsoft.com>; Sasha
> Levin
> > <Alexander.Levin at microsoft.com>
> > Cc: Wei Hu <weh at microsoft.com>; Dexuan Cui <decui at microsoft.com>
> > Subject: [PATCH] video: hyperv_fb: Fix hibernation for the deferred IO feature
> >
> > fb_deferred_io_work() can access the vmbus ringbuffer by calling
> > fbdefio->deferred_io() -> synthvid_deferred_io() -> synthvid_update().
> >
> > Because the vmbus ringbuffer is inaccessible between hvfb_suspend() and
> > hvfb_resume(), we must cancel info->deferred_work before calling
> > vmbus_close() and then reschedule it after we reopen the channel in
> > hvfb_resume().
> >
> > Fixes: a4ddb11d297e ("video: hyperv: hyperv_fb: Support deferred IO for
> > Hyper-V frame buffer driver")
> > Fixes: 824946a8b6fb ("video: hyperv_fb: Add the support of hibernation")
> > Signed-off-by: Dexuan Cui <decui at microsoft.com>
> > ---
> >
> > This patch fixes the 2 aforementioned patches on Sasha Levin's Hyper-V tree's
> > hyperv-next branch:
> >
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kern
> > el.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fhyperv%2Flinux.git%2Flog
> > %2F%3Fh%3Dhyperv-
> >
> next&data=02%7C01%7Cweh%40microsoft.com%7C451143ff78f04401d9
> > 6f08d76d893a84%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637
> >
> 098308493217121&sdata=P2fo%2F1TJUMIj5FtJCOp2QwDrghhVfPSCEJ4f1
> > vkOXvI%3D&reserved=0
> >
> > The 2 aforementioned patches have not appeared in the mainline yet, so
> please
> > pick up this patch onto he same hyperv-next branch.
> >
> >  drivers/video/fbdev/hyperv_fb.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
> > index 4cd27e5172a1..08bc0dfb5ce7 100644
> > --- a/drivers/video/fbdev/hyperv_fb.c
> > +++ b/drivers/video/fbdev/hyperv_fb.c
> > @@ -1194,6 +1194,7 @@ static int hvfb_suspend(struct hv_device *hdev)
> >  	fb_set_suspend(info, 1);
> >
> >  	cancel_delayed_work_sync(&par->dwork);
> > +	cancel_delayed_work_sync(&info->deferred_work);
> >
> >  	par->update_saved = par->update;
> >  	par->update = false;
> > @@ -1227,6 +1228,7 @@ static int hvfb_resume(struct hv_device *hdev)
> >  	par->fb_ready = true;
> >  	par->update = par->update_saved;
> >
> > +	schedule_delayed_work(&info->deferred_work, info->fbdefio->delay);
> >  	schedule_delayed_work(&par->dwork, HVFB_UPDATE_DELAY);
> >
> >  	/* 0 means do resume */
> > --
> > 2.19.1
> 
> Signed-off-by: Wei Hu <weh at microsoft.com>

Sorry, please disregard the Signed-off-by line I added above. It was my mistake.
should be:

Reviewed-by: Wei Hu <weh at microsoft.com>