Mark Lord wrote: > Tejun Heo wrote: >> Hello, >> >> Stuart MENEFY wrote: >>> libata keeps a shadow copy of the ATA CTL register (which is write >>> only), >>> and only writes to the hardware when the required value doesn't match >>> the shadow. However this copy wasn't being maintained when performing >>> reset functions. This could cause problems for the first operation after >>> a reset when the correct value might not be written to the CTL register. >>> >>> This problem was observed when hotplugging a drive: the identify command >>> was being issued with interrupts enabled, when they should have been >>> disabled. >>> >>> Signed-off-by: Stuart Menefy <stuart.menefy@xxxxxx> >> >> Nice catch. Maybe a nice addition would be a ata_sff_write_to_ctl() >> or something which always does the right thing. >> >> Acked-by: Tejun Heo <tj@xxxxxxxxxx> > .. > > Mmm.. I wonder if this is severe enough to warrant backporting > to -stable for the past couple of releases? Yeah, I think it can be responsible for at least some of runaway IRQs during detection on ata_piix and is likely to be a good candidate for -stable but I think it would be better to see how it does on -rc first for a while before pushing this -stable. sata_nv breakages very well showed how messed up things can get with obvious fixes. :-) Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
