[PATCH] scripts/runqemu-internal: Work around qemux86 PAT bugs in linux 4.4.1

[PATCH] scripts/runqemu-internal: Work around qemux86 PAT bugs in linux 4.4.1

[Richard Purdie]

Since the upgrade of qemux86 to 4.4.1 we're seeing PAT issues when
starting the X server. We need to fix the problem but the failing
sanity tests mask out other issues and we need a workaround.

Merge this for now until we can figure out the full issue. This is
better than changing the kernel defconfig or reverting to old
kernel versions.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/scripts/runqemu-internal b/scripts/runqemu-internal
index ebed2bd..ad854d1 100755
--- a/scripts/runqemu-internal
+++ b/scripts/runqemu-internal
@@ -434,7 +434,7 @@ if [ "$MACHINE" = "qemux86" ]; then
     fi
     # Currently oprofile's event based interrupt mode doesn't work(Bug #828) in
     # qemux86 and qemux86-64. We can use timer interrupt mode for now.
-    KERNCMDLINE="$KERNCMDLINE oprofile.timer=1"
+    KERNCMDLINE="$KERNCMDLINE oprofile.timer=1 nopat"
 fi
 
 if [ "$MACHINE" = "qemux86-64" ]; then

Re: [PATCH] scripts/runqemu-internal: Work around qemux86 PAT bugs in linux 4.4.1

[Bruce Ashfield]

On 2016-02-12 1:00 PM, Richard Purdie wrote:
> Since the upgrade of qemux86 to 4.4.1 we're seeing PAT issues when
> starting the X server. We need to fix the problem but the failing
> sanity tests mask out other issues and we need a workaround.
>

I was out of the day and didn't notice if any logs were available
for the issue ? Is there a pointer to the failing logs ?

Obviously I didn't notice this in any of my runs. I'll check 4.4.x
for anything that looks suspicious, and can bisect if needed.

Bruce

> Merge this for now until we can figure out the full issue. This is
> better than changing the kernel defconfig or reverting to old
> kernel versions.
>
> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
>
> diff --git a/scripts/runqemu-internal b/scripts/runqemu-internal
> index ebed2bd..ad854d1 100755
> --- a/scripts/runqemu-internal
> +++ b/scripts/runqemu-internal
> @@ -434,7 +434,7 @@ if [ "$MACHINE" = "qemux86" ]; then
>       fi
>       # Currently oprofile's event based interrupt mode doesn't work(Bug #828) in
>       # qemux86 and qemux86-64. We can use timer interrupt mode for now.
> -    KERNCMDLINE="$KERNCMDLINE oprofile.timer=1"
> +    KERNCMDLINE="$KERNCMDLINE oprofile.timer=1 nopat"
>   fi
>
>   if [ "$MACHINE" = "qemux86-64" ]; then
>
>

Re: [PATCH] scripts/runqemu-internal: Work around qemux86 PAT bugs in linux 4.4.1

[Richard Purdie]

On Fri, 2016-02-12 at 17:04 -0500, Bruce Ashfield wrote:
> On 2016-02-12 1:00 PM, Richard Purdie wrote:
> > Since the upgrade of qemux86 to 4.4.1 we're seeing PAT issues when
> > starting the X server. We need to fix the problem but the failing
> > sanity tests mask out other issues and we need a workaround.
> > 
> 
> I was out of the day and didn't notice if any logs were available
> for the issue ? Is there a pointer to the failing logs ?
> 
> Obviously I didn't notice this in any of my runs. I'll check 4.4.x
> for anything that looks suspicious, and can bisect if needed.

Your inbox should have details of it under "poky: update qemu* to
prefer 4.4 kernel", the logs are in there. There was a promising
looking patch upstream but it didn't help.

It reproduced easily with a "MACHINE=qemux86 bitbake core-image-sato;
runqemu qemux86" and then watch X fail to start.

It also looks like we have a new perf race:

https://autobuilder.yoctoproject.org/main/builders/nightly-x86-64/build
s/657/steps/BuildImages/logs/stdio

Cheers,

Richard