On Friday 16 March 2007, Mark Lord wrote: > Jeff Garzik wrote: > > Alan Cox wrote: > >>> I think it only requires the *host* to drop to PIO0 timings. In > >>> which case it should be achievable w/o libata modification -- if the > >>> driver has to "snoop" command and turn off prefetch, why not switch > >>> to PIO0 temporarily? > >> > >> This isn't a big issue. Eventually we have to support sending speed > >> change commands and once we do that the caller will be able to switch to > >> PIO0 and back again. > > > > We should be pretty close to that. One of the bigger blockages is > > needing to stop (freeze) all ports, before performing an out-of-band SET > > FEATURES and related tuning. > > For this particular feature, READ/WRITE LONG, > none of this is actually necessary in practice on common controllers. It still would be nice to add a comment documenting issues raised by Sergei so if somebody actually hits a problem on not-so-common controller she/he will know what to look for. > I've tested ATA1 and newer PATA drives, and various SATA drives > with these commands without bothering to drop to PIO0, > and none of them had issues. This is what really matters wrt libata READ/WRITE LONG support. These commands are not supposed to be used by normal users anyway so patch while not being "perfect" is "good enough" to be merged IMO. Bart - 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
