Re: Boot problem on PPC with 4.4-git - Bisected to commit 21266be

[Larry Finger]

On 01/20/2016 02:16 PM, Dan Williams wrote:
> On Wed, Jan 20, 2016 at 12:08 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> > On Wed, Jan 20, 2016 at 12:01 PM, Larry Finger
> > <Larry.Finger@xxxxxxxxxxxx> wrote:
> > > My PowerBook G4 Aluminum with a 32-bit PPC processor fails to boot for the
> > > 4.4-git series. The problem was bisected to commit 21266be. It took a while
> > > to figure out why a commit that only rearranges the Kconfig files could
> > > cause the problem.
> > >
> > > The answer came when I read the commit message for 90a545e98126 and saw that
> > > "Recompiling with CONFIG_IO_STRICT_DEVMEM=n" might be necessary. After I
> > > made that change, the system boots.
> > >
> > > If it is the graphics hardware driver at fault, the VGA controller is listed
> > > as an ATI RV350 [Mobility Radeon 9600 M10] with PCI ID 1002:4350. It uses
> > > radeon as the driver.
> > >
> > > I'm not sure if this is a bug in the configuration, but I know that
> > > selecting the default answer to all the new configuration parameters leaves
> > > me with a machine that is unbootable.
> >
> > I agree that the default configuration should remain bootable.  I'll
> > send a change that does not force that default.
> >
> > Thanks for the report and sorry for the inconvenience.
>
> Are you sure that the bisect is pointing to "21266be9ed54 arch:
> consolidate CONFIG_STRICT_DEVM in lib/Kconfig.debug" and not
> "90a545e98126 restrict /dev/mem to idle io memory ranges"?  The
> default for CONFIG_STRICT_DEVM should be unchanged in 21266be9ed54,
> it's not until 90a545e98126 that I would expect a behavior change.

Yes. Commit 21266be9ed54 was the reported bad commit; however, the previous test 
kernel was 90a545e98126. In fact, I was struck that the final bisection build 
did not change any object files, thus you are right that 90a545e98126 is likely 
the bad commit.

Larry