On Wed, Feb 3, 2010 at 7:24 PM, Tejun Heo <tj@xxxxxxxxxx> wrote: > On 02/04/2010 11:37 AM, Grant Grundler wrote: >> I had two questions on that thread that never got answered: >> http://markmail.org/message/snpekoj4qexrslk5 >> >> | How can we find out if anyone has the SEMB properly wired up? >> | Would it be hard to make libata aware of "SEMB port not responding" case? >> | ie if the SEMB port times out or has no link, reduce the port count of >> | the sil3726 PMP by one. >> | >> | Maybe add a "enable_sil24_semb" flag to libata? >> | (avoid checking unless someone asks for it). I hate magic flags but also >> | don't want to subject most people to the timeout delay. >> >> I (or Gwendal) can post a patch (and lightly test) for any of the above. >> Just need to get some guidance so we don't waste our time. > > It's not really sil24 tho. But anyways, I think we can just disable > them altogether. It's not like they have ever worked. Just limiting > both 3726 and 4726 to 5 ports should be fine. Sorry - You are right. I meant "enable_sil3726_semb". I'm not sure we need to limit the SEMB ports anymore either. See below. > That said, I'm not > quite sure this is relevant to the reported problem but it's worth a > shot. I didn't have a better idea. I'm seeing this in sata_pmp_quirks() since ATA_LFLAG_NO_SRST was introduced: 337 static void sata_pmp_quirks(struct ata_port *ap) 338 { 339 u32 *gscr = ap->link.device->gscr; 340 u16 vendor = sata_pmp_gscr_vendor(gscr); 341 u16 devid = sata_pmp_gscr_devid(gscr); 342 struct ata_link *link; 343 344 if (vendor == 0x1095 && devid == 0x3726) { 345 /* sil3726 quirks */ 346 ata_for_each_link(link, ap, EDGE) { 347 /* Class code report is unreliable and SRST 348 * times out under certain configurations. 349 */ 350 if (link->pmp < 5) 351 link->flags |= ATA_LFLAG_NO_SRST | 352 ATA_LFLAG_ASSUME_ATA; 353 354 /* port 5 is for SEMB device and it doesn't like SR ST */ 355 if (link->pmp == 5) 356 link->flags |= ATA_LFLAG_NO_SRST | 357 ATA_LFLAG_ASSUME_SEMB; 358 } But the ATA_LFLAG_NO_SRST used in line 351 is not present in the 2.6.26 tree I know works with PMPs. The original commit comment isn't specific about exactly which HW had problems: http://www.mail-archive.com/git-commits-head@xxxxxxxxxxxxxxx/msg24335.html "Some links on some PMPs locks up on SRST and/or report incorrect device signature. Implement ATA_LFLAG_NO_SRST, ASSUME_ATA and ASSUME_SEMB to handle these quirky links. NO_SRST makes EH avoid SRST. ASSUME_ATA and SEMB forces class code to ATA and SEMB_UNSUP respectively. Note that SEMB isn't currently supported yet so the _UNSUP variant is used." Can you publish which PMP implementations sometimes lock up on SRST? I doubt this is related to the problem Chandra is seeing but again, don't have better ideas. BTW, this same kernel works fine without disabling port 5 (SEMB port). I didn't know this until I just looked. I know previous source trees Google used ignored SEMB port on 3726 and I mistakenly assumed this one did too. :( thanks, grant -- 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
