Messages in this thread | | | Date | Fri, 10 Jan 2003 05:03:40 -0800 (PST) | From | Andre Hedrick <> | Subject | Re: Problem in IDE Disks cache handling in kernel 2.4.XX |
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Oh, just let the darn thing barf a 0x51/0x04 is fine with me! Just an abort/unsupported command.
Cheers,
On 10 Jan 2003, Alan Cox wrote:
> On Fri, 2003-01-10 at 11:14, Andre Hedrick wrote: > > The drive does random and automatic flush caches, if an error happens it > > does not report. *sigh* When APM hits it with a flush and pray the error > > is from this flush, but it does not matter ... the kernel does not have > > the paths to deal this issue ... so bye bye data! Now it if the current > > flush is not the owner of the error OMFG is suggested. > > For that matter the BIOS tends to issue the flush, in fact APM is > supposed to be transparent so the BIOS is required to handle it and > since a critical shutdown from the APM PM might not even hit the OS > it has to. Of course pigs also fly 8) > > > > > I had a look at patch 2.4.21pre3 and the code looks the same. > > > > > > > > And by the way how are powered off the IDE drives ? > > > > Because a FLUSH CACHE or STANDY or SLEEP is MANDATORY before powering off the > > > > drive with cache enabled or you will enjoy lost data > > > > > > IDE disagrees with itself over this but when we get a controlled power > > > off we do this. The same ATA5/ATA6 problem may well be present there > > > too. I will review both > > > > Not true, the firmware knows to commit the data to platter. > > If it was true you would be screaming long ago. > > IDE disagrees with itself because it is meant to work compatibly but if > you run it compatibly you lose data on poweroff. > > > > > > Any specific opinion Andre ? > > > > A dirty trick used to date is to pop the STANDY or SLEEP, and depend on > > the drive to deal with the double dirty flush error. If the FLUSH CACHE > > was not valid, the drive would spin back up from STANDY, but not from > > SLEEP, this could be a problem. However SLEEP issued by the driver only > > happens at shutdown unless it has been changed. In the shutdown process, > > each partition unmount was flushed and also once extra when the usage > > count was set to zero. Worst case was 2 flush min. > > > > The original question however is whether we are skipping issuing the flush > and sleep on ATA3-5 devices when we should not, because the test is over > strong. > > It seems weakening the test is the best option, it fixes ATA-5 and any device > told to sleep, standby or flush that doesn't know the command is just going > to go "Huh ?" and we'll get a nice easy to handle error. > > Alan > >
Andre Hedrick LAD Storage Consulting Group
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