On Sat, Dec 19, 2009 at 10:51 PM, Luis R. Rodriguez <mcgrof@xxxxxxxxx> wrote: > On Sat, Dec 19, 2009 at 9:01 PM, Larry Finger <Larry.Finger@xxxxxxxxxxxx> wrote: >> In exploring the cause of DMA errors for BCM4312 devices on Atom >> processors, other drivers that work write to PCI configuration >> register 0x40. The code fragment below was found in the open-code >> portion of the Broadcom hybrid wl driver. It is also used in the >> ipw2100 and ath9k drivers. In the latter case, it had been removed >> and later restored to prevent fatal interrupt errors. > > I should note 0x40 starts with vendor specific PCI config space so you > cannot guarantee different PCI devices use 0x41 will be used the same > for different devices. The documentation for the ath9k PCI-E devices > used that entry for something completely different but what I did not > do is try to very and ensure PCI devices do not use it it for the > same. I am told though that although this is PCI vendor space some > devices may still use similar private PCI config spaces on different > devices which just follows a practice. At this point we now have not > only b43, ipw and ath9k follow this but also prism54 and I think p54 > uses this. I'll note I *highly* doubt this is used for the same thing > on all these devices and was just code copied from other Linux > drivers. In the case of Atheros Linux drivers I know it was copied > form Intel drivers, which is why I started questioning it all. > > Anyway, if it helps, that's great :) but it cannot be concluded its > all for the same thing unless you have proper documentation as this is > in PCI vendor space which *can* vary depending on device and vendor. Larry, does this actually fix something or is this code purely speculative? Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
