Hi, Jeff.
On Apr 19 2009, Jeff Garzik wrote:Michael Tokarev wrote:Well, the kernel does a good job here in *almost* all cases.Do you have a log?
The problematic case is when a device has some bad/unreadable
blocks/sectors. When such a place occurs on read, libata
(or whatever it is) performs several retries, each time
using "less aggressive" settings - like reducing UDMA and
PIO mode till the lowest possible PIO/33. And the device
stays in that mode until reboot, even if the problematic
sector has been relocated. So it'd be nice to be able to
reset the mode back in such cases.
I have a log here of libata reducing UDMA speed. I don't know if this is
any hardware problem or not (I think not), but I do see libata
complaining and reducing the speed of the drive.