Messages in this thread | | | From | Denis Vlasenko <> | Subject | Re: Bug in linux kernel when playing DVDs. | Date | Wed, 30 Apr 2003 15:08:39 +0300 |
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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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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