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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Tong Zhang <ztong0001@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Sam Ravnborg <sam@ravnborg.org>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Linux Fbdev development list <linux-fbdev@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] video: fbdev: pm2fb: avoid stall on fb_sync
Date: Wed, 24 Feb 2021 12:35:37 +0100	[thread overview]
Message-ID: <CAMuHMdWM5z-vKRwhCgJHjU-S_L0WR=avmDN-b8dN87b=rgi08w@mail.gmail.com> (raw)
In-Reply-To: <CAA5qM4D0y9-gL7AAMQvtwrfJC_UvSTB5_S5PX3qkYSxHRUS-Qw@mail.gmail.com>

Hi Tong,

On Sun, Feb 21, 2021 at 1:05 AM Tong Zhang <ztong0001@gmail.com> wrote:
> On Sat, Feb 20, 2021 at 6:33 PM Randy Dunlap <rdunlap@infradead.org> wrote:
> > On 2/20/21 3:02 PM, Tong Zhang wrote:
> > > pm2fb_sync is called when doing /dev/fb read or write.
> > > The original pm2fb_sync wait indefinitely on hardware flags which can
> > > possibly stall kernel and make everything unresponsive.
> > > Instead of waiting indefinitely, we can timeout to give user a chance to
> > > get back control.
> >
> > Is this a real problem or theoretical?
> > Does someone still use this driver?
>
> I currently have this problem on my machine.
> I have submitted a revised patch -- which includes the console log.

Your machine is "QEMU Standard"?
Can this happen on real hardware, too, or is this a deficiency in QEMU,
which should be fixed there?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

  reply	other threads:[~2021-02-24 11:36 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-20 23:02 [PATCH] video: fbdev: pm2fb: avoid stall on fb_sync Tong Zhang
2021-02-20 23:32 ` Randy Dunlap
2021-02-21  0:00   ` [PATCH v2] " Tong Zhang
2021-02-21  0:35     ` Randy Dunlap
2021-02-21  2:28       ` [PATCH v3] " Tong Zhang
2021-02-21  2:34       ` [PATCH v2] " Tong Zhang
2021-02-21  0:00   ` [PATCH] " Tong Zhang
2021-02-24 11:35     ` Geert Uytterhoeven [this message]
2021-02-24 12:24       ` Tong Zhang
2021-02-21  0:51 ` kernel test robot
2021-02-21  2:02 ` kernel test robot

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