Alan wrote: >> This patch makes amd74xx not configure udma mode higher than BIOS did. >> If BIOS configured the device <= udma44, udma33 is the maximum speed. > > NAK > > The boot firmware for AMD/Nvidia chips is only run on PC, and the data is > only valid on some of them, in some cases, and not after a suspend/resume > cycle. You cannot rely on the BIOS (if any) loaded register values. Since > you've posted patches to clean up the drive side detect (when tweaked > with a couple of fixes), this hack won't be neccessary. If BIOS hasn't run, UDMA timing wouldn't have been programmed and as such the speed won't be limited. So, there should be no harm done in that case. Even if something goes really wrong, the worst happens is capping speed to udma33. The reason why I posted both drive side wire detection and this was that both are often wrong on my test machine. It's one of the popular NF4 boards from ASUS, probably one of the most sold. I've tested with one fairly recent samsung drive and two old drives from maxtor and wd. All of them support > udma33. In many valid configurations using 40c, both the host and drive reported 80c (I verified register values multiple times) and configured accordingly by both pata_amd and amd74xx and then of course cause a lot of transfer errors. In all those cases, BIOS configured transfer mode correctly. So, without this patch, amd74xx will drop out of dma mode as soon as it gets detected in many configurations. So, I think the benefit (correct configuration on most machines) easily outweighs the danger (incorrectly capping speed to working udma33 on non-PC). -- 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
