From: Denis Vlasenko <vda@port.imtp.ilyichevsk.odessa.ua>
To: James Courtier-Dutton <James@superbug.demon.co.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Bug in linux kernel when playing DVDs.
Date: Wed, 30 Apr 2003 15:08:39 +0300 [thread overview]
Message-ID: <200304301201.h3UC19u23911@Port.imtp.ilyichevsk.odessa.ua> (raw)
In-Reply-To: <3EAE5DF5.1040209@superbug.demon.co.uk>
On 29 April 2003 14:11, James Courtier-Dutton wrote:
> >See? Sector # is increasing... Linux retries the read several times,
> >then reports EIO to userspace and goes to next sectors.
> > Unfortunately, they are bad too, so the loop repeats. Eventually it
> > will pass by all bad sectors (if not, it's a bug) but it can take
> > longish time.
> >
> >Apart of making max retry # settable by the user, I don't see how
> >this can be made better. Pity. This is common problem on CDs...
>
> What is this EIO report. The CPU is never returned to user space
> apps, so the app never sees any error.
Are you sure that CPU never returned to the app?
(strace is your friend...)
> As for retries, for DVD playing we do not want the Linux kernel to do
> any retries, because during DVD playback, we just want a very quick
> response saying there was an error.
Kernel is not yet telepathic.
> The DVD playing application can
> then skip forward 0.5 seconds and continue. If one sector fails on a
> DVD, there is little or not point in reading the next sector. One has
> to start reading from the next VOBU. (i.e. about 0.5 seconds skip.)
You need a way to tell kernel that you want such behavior.
"skip 0.5 sec on error" requirement is rather hard
to describe to the kernel.
--
vda
next prev parent reply other threads:[~2003-04-30 11:58 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-27 10:47 Bug in linux kernel when playing DVDs James Courtier-Dutton
2003-04-29 5:46 ` Denis Vlasenko
2003-04-29 6:56 ` Nick Piggin
2003-04-30 12:10 ` Denis Vlasenko
2003-04-30 12:07 ` Alan Cox
2003-04-30 15:23 ` James Courtier-Dutton
2003-04-30 14:32 ` Alan Cox
2003-04-30 16:46 ` Elladan
2003-04-30 17:16 ` Jan Knutar
2003-04-29 11:11 ` James Courtier-Dutton
2003-04-30 12:08 ` Denis Vlasenko [this message]
2003-04-30 12:29 ` Richard B. Johnson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200304301201.h3UC19u23911@Port.imtp.ilyichevsk.odessa.ua \
--to=vda@port.imtp.ilyichevsk.odessa.ua \
--cc=James@superbug.demon.co.uk \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).