Re: Possible bug in ide_cd_queue_pc() or ide_wait_stat() ?

[Borislav Petkov <bp@alien8.de>]

From: Dominic Curran <dominic.curran@citrix.com>
Date: Wed, Jul 28, 2010 at 04:23:13PM +0100

> Borislav Petkov wrote:
> >>I have some TEAC DV-28E-V CDROM drives that after polling for status
> >>starts to timeout requests (the time it takes to do this varies
> >>between 5mins and 24hrs).
> >
> >Which kernel is that? Can we see a complete dmesg? Which tool does the
> >polling (udev... )?
> >
> We have cooked our own usermode tool (we dont use udev).
> Tool is very simple:
> 1) polls cdrom drive using ioctl CDROM_DRIVE_STATUS
> 2) Looks for a CDS_DISC_OK return
> 3) Once it sees that it tries to mount CD
> 
> The problem is that for this specific drive it starts timing out
> STATUS requests, and then returns CDS_DISC_OK.
> This cause the tools to try to mount (non existent disc), which then
> eats 100% cpu time.
> 
> So even if the drive goes bad, I'd like to get back a error status
> from the ioctl rather than CDS_DISC_OK.

Right, I think I see the issue after staring at your instrumentation
below and the code, however...

> Kernel is 2.6.27.  Based on CentOS I believe.

this is an awfully old kernel and Bart and I broke^W (cough) changed a
lot (cough) :) in ide since then so I'd like to verify your issue with a
recent kernel first (current 35-rc6 is stable enough, it seems) before
we get on with debugging it further.

Thanks.

-- 
Regards/Gruss,
    Boris.