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. 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
