Hi Erik, On Tue, 20 Nov 2018 18:30:22 +0000, Schmauss, Erik wrote: > > -----Original Message----- > > From: Greg KH [mailto:greg@xxxxxxxxx] > > Sent: Tuesday, November 20, 2018 1:12 AM > > To: Jean Delvare <jdelvare@xxxxxxx> > > Cc: stable@xxxxxxxxxxxxxxx; Guenter Roeck <linux@xxxxxxxxxxxx>; > > Schmauss, Erik <erik.schmauss@xxxxxxxxx>; Wysocki, Rafael J > > <rafael.j.wysocki@xxxxxxxxx> > > Subject: Re: Please revert "ACPICA: AML interpreter: add region addresses in > > global list during initialization" > > > > On Tue, Nov 20, 2018 at 10:03:59AM +0100, Jean Delvare wrote: > > > On Tue, 20 Nov 2018 09:54:19 +0100, Greg KH wrote: > > > > Ok, I'll go revert this, but shouldn't it also be reverted in > > > > Linus's tree as well? > > > > > > No. As I understand it (with my limited knowledge of ACPICA), the > > > change itself is correct. The problem is that it will detect resource > > > conflicts which were unnoticed before, and that will prevent drivers > > > from loading. Some of them may be addressed with driver fixes or new > > > drivers. Others are false positives (due to bogus BIOS) which users > > > will have to work around with acpi_resource_conflicts=lax. We have > > > been through this before, nothing new really, but it takes years to > > > address such problems. This just can't be done in stable kernel series. > > I would like to give you more context. > > There was a fairly complicated change that occurred in 4.17 and we > caused a regression by forgetting to add region addresses in a global list > during operation region initialization. We found the regression when bug > reporters tried to boot their macbook pro and asus laptop and saw that > there was a difference in behavior when drivers are being loaded Commit 4abb951b73ff0a8a979113ef185651aa3c8da19b has no Fixes tag. Which commit introduced the regression? Can you point me to the associated bug reports? > So what I am trying to say is that we have been emitting these errors for a > while before we caused the regression. The goal with this patch is to keep > the behavior the same as kernels older than 4.17 where warnings are > printed to dmesg due to resource conflicts. Fine with me for upstream, but I still need to be convinced that it belongs to stable series. For now, the only 2 related bugs I know of are #200011 (which is NOT fixed by commit 4abb951b73ff0a8a979113ef185651aa3c8da19b) and #201721 (which is caused by that commit). 1 vs 0, revert wins. If you want me to change my mind, you must provide additional data points proving that commit 4abb951b73ff0a8a979113ef185651aa3c8da19b solves more functional regressions than it causes. Thanks, -- Jean Delvare SUSE L3 Support
