Hi, Bjorn >> >> > Fix system hang issue: if first accessed resource file of BAR0 ~ >> >> > BAR4, system will hang after executing lspci command >> >> >> >> This needs more explanation. We've already read the BARs by the >> >> time header quirks are run, so apparently it's not just the mere >> >> act of accessing a BAR that causes a hang. >> >> >> >> We need to know exactly what's going on here. For example, do >> >> BARs >> >> 0-4 exist? Does the device decode accesses to the regions >> >> described by the BARs? The PCI core has to know what resources >> >> the device uses, so if the device decodes accesses, we can't just >> >> throw away the start/end information. >> > The BARs 0-4 is exist and the PCI device is enable IO space, but >> > user access >> the regions file by udevadm command with info parameter, the system will hang. >> > Like this: udevadmin info --attribut-walk >> --path=/sys/device/pci-device/000:*. >> > Because the device is just AHCI host controller, don't need the >> > BAR0 ~ 4 region >> file. >> > Is my explanation ok for the patch? >> >> No, I still don't know what causes the hang; I only know that udevadm >> can trigger it. I don't want to just paper over the problem until we >> know what the root cause is. >> >> Does "lspci -H1 -vv" also cause a hang? What about "setpci -s<dev> >> BASE_ADDRESS_0"? "setpci -H1 -s<dev> BASE_ADDRESS_0"? > The commands are ok because the commands can't find the device after accessing IO port. > The root cause is that accessing of IO port will make the chip go bad. So, the point of the patch is don't export capability of the IO accessing. >Ah, so the problem is not with accessing the BAR in config space. The problem is with accessing the I/O port space mapped by the BAR. Is that right? Yes... >Does "udevadm info --attribute-walk" really access the device address space mapped by the BARs? The older version maybe will access the space, I just got the info from HP. And I simplify the issue by executing following command: Cat /sys/devices/pci-device/**/resourceX I want to set the resources of BAR0 ~ 4 to 0 to avoid the IO accessing by user. Any question? Thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
