Re: [regression] CD-ROM polling blocks suspend on some machines (Re:[PATCH 1/2] cdrom: always check_disk_change() on open)

From: Tejun Heo
Date: Sat Sep 03 2011 - 22:43:09 EST


Hello,

On Sat, Sep 03, 2011 at 05:14:56PM -0500, Jonathan Nieder wrote:
> Various people[1] have been noticing a race (or races?) in which the
> cdrom_id and scsi_id programs from udev can get stuck in the D state
> if udev doesn't sleep a little while before running them. This
> prevents the machine from suspending. The problem was discovered with
> Debian kernels
>
> 2.6.39-1
> 2.6.39-2
> 3.0.0-1
>
> and was not experienced with kernel
>
> 2.6.38-5
>
> (These kernels are closely based on v2.6.39, v2.6.39.1, v3.0, and
> v2.6.38.5, respectively.) Reverting commit bf2253a6f00e (cdrom:
> always check_disk_change() on open, 2011-04-29) seems to avoid
> trouble.
>
> One common theme seems to be DVD drives. Details at [1].
>
> Known problem? Any ideas for tracking it down?

Can you please build vanilla kernel with CONFIG_FRAME_POINTER turned
on, reproduce the problem and attach full dmesg output?

Thanks.

--
tejun
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