Messages in this thread | | | Date | Fri, 3 Sep 2004 16:50:54 +0200 | From | Jens Axboe <> | Subject | Re: Nasty IDE crasher in 2.6.9rc1 |
| |
(suse.dk is not related to suse.de and it helpfully eats all messages sent to unknown users. not so great :(
On Tue, Aug 31 2004, Alan Cox wrote: > You never never issue unknown commands to drives. Thats how Mandrake destroyed > CD-ROM drives. I knew this was in -mm and supposed to be getting sorted I was > somewhat horrified to find it in 2.6.9rc1. > > This patch crashes two of my CF cards (one so badly you have to reformat it > to get it back) and anything attached to an IT8212 controller. The correct > fix is to do what the standard actually says and always check for cache > flush. Contrary to the comment in the patch drives do report this correctly > its just that some of them nop unknown commands. > > Please fix this patch segment for rc2, its not just wrong, its dangerous.
Ugh, that's bad. I agree with the change, thanks. Linus passed it on.
> Another problem with barrier is that it can take several minutes worst case > for the command to complete on a large modern drive (timings c/o friendly > ide drive engineer). That causes two problems I've pointed out to Jens that > we need to fix before barriers are IMHO production grade
Can you pass me his results?
> 1. Anything based on fairness and latency is screwed. Throughput > apparently is up so it makes sense for some users, and probably > for others we should write cache off as Jens suggested.
Yes, it's a tradeoff. The user can decide himself what is most important. It all depends on the work load, of course.
> 2. The timeouts on the command issue appear to be too small, and > we will time out and reset the drive in loaded situations.
You don't seem to address that in your patch?
> Thankfully next generation ATA has both cache bypass writes and tagging.
But the tagging still isn't useful for this. Have they added WIN_WRITE_DMA_EXT_QUEUED_FUA?
-- Jens Axboe
- 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/
| |