On Sunday, April 15, 2012, Rafael J. Wysocki wrote: > On Sunday, April 15, 2012, Mikko Vinni wrote: > > From: Rafael J. Wysocki: > > > > >> > Please change that dev_dbg() in pci_restore_state() into dev_info() > > >> > and see how many times it gets printed with the commit applied (not > > > reverted). > > >> > > >> > > >> I ran the dmesg through "uniq -c" and it looks like this: > > >> > > >> 1 ACPI: Low-level resume complete > > >> 1 PM: Restoring platform NVS memory > > >> 1 Enabling non-boot CPUs ... > > >> 1 Booting Node 0 Processor 1 APIC 0x1 > > >> 1 CPU1 is up > > >> 1 ACPI: Waking up from system sleep state S3 > > >> 10 pcieport 0000:00:02.0: restoring config space at offset 0x7 (was > > > 0x20005151, writing 0x5151) > > > > > > Well, yeah. So the commit you bisected it to is total and utter crap. > > > Most importantly, it retries the writes for all of the dwords in the > > > device's > > > config space _including_ the status register (which by definition need not be > > > the same as the written value). > > > > > > I wonder if the appended patch helps? > > > > It does. It seems there is a change only in the devices that refuse to wake up; > > somehow writing too many times to them affects the rest of the machine. > > So, for this machine your patch fixes the problem of the touchpad not working. > > Good, thanks for the confirmation. :-) > > > The write is now attempted (at most) 11 times, as shown below. Probably not > > a huge deal. > > > > 1 ACPI: Waking up from system sleep state S3 > > 11 pcieport 0000:00:02.0: restoring config space at offset 0x1c (was 0x20005151, writing 0x5151) > > Well, here you see that the PCI Express port is refusing to accept a new BAR value. > It seems not to be operational and this probably is the reason why the device below > the port don't respond later. > > I'm not sure why that happens, though. OK, I know. There simply are fewer BARs for bridges (and PCIe ports) and here we're attempting to overwrite the secondary status register. Sigh. Well, I guess we should only retry the writes to BARs for Type 0 headers. Thanks, Rafael -- 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
