On Tue, Apr 02, 2013 at 09:23:36AM -0700, Greg Kroah-Hartman wrote: > On Tue, Apr 02, 2013 at 11:53:44AM -0400, Josh Boyer wrote: > > Hi All, > > > > We've had a report [1] that the 3.8.4 stable kernel makes a PNP serial > > port stop working. After testing 3.8.3, the reporter narrowed it down > > to stable commit eec98f82c637 (tty/8250_pnp: serial port detection > > regression since v3.7) (upstream commit 77e372a3d82). Reverting that > > single commit from 3.8.5 allows the serial port to continue working. > > > > The machine in question is using an AMI UEFI implementation as the > > firmware, and on 3.8.3 the serial port has the following in > > /sys/bus/pnp/devices/00:0a/resources > > > > state = active > > io disabled > > irq 4 > > dma disabled > > > > With 3.8.[45], the same file has: > > > > state = disabled > > io disabled > > irq 4 > > dma disabled > > > > In both cases, the io and dma resources are disabled, and an IRQ is > > assigned. However, the state remains active for the port on 3.8.3. > > > > The offending commit mentions this is a BIOS bug from InsydeH2O and that > > the port is bogus in that case, but we have something similar here with > > an AMI UEFI implementation (Version: 0406 Release Date: 06/06/2012) > > where the port isn't bogus. > > > > I'm not sure exactly what the solution should be here. Any thoughts? > > Sean, should I just revert this patch now, and wait for a better fix > later? Looks like although the pnp io is disabled, it does contain a valid port number, else pnp detection would fail in 3.8.3. We're a little stricter in 3.8.4, but it should fall back to legacy port detection -- the port and irq are standard. I don't understand why the legacy port detection (see SERIAL_PORT_DFNS) isn't working. Since the fallback isn't working properly maybe this patch should be reverted for now. If the pnp information had some virtue we wouldn't have these problems. Sean -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
