On Thu, Oct 27, 2022 at 2:10 PM Ville Syrjälä
wrote:
>
> On Thu, Oct 27, 2022 at 01:55:39PM -0600, jim.cro...@gmail.com wrote:
> > On Thu, Oct 27, 2022 at 9:59 AM Ville Syrjälä
> > wrote:
> > >
> > > On Thu, Oct 27, 2022 at 09:37:52AM -0600, jim.cro...@gmail.com wrote:
> > > > On Thu, Oct 27, 2022 at 9:08 AM Jason Baron wrote:
> > > > >
> > > > >
> > > > >
> > > > > On 10/21/22 05:18, Jani Nikula wrote:
> > > > > > On Thu, 20 Oct 2022, Ville Syrjälä
> > > > > > wrote:
> > > > > >> On Sat, Sep 24, 2022 at 03:02:34PM +0200, Greg KH wrote:
> > > > > >>> On Sun, Sep 11, 2022 at 11:28:43PM -0600, Jim Cromie wrote:
> > > > > hi Greg, Dan, Jason, DRM-folk,
> > > > >
> > > > > heres follow-up to V6:
> > > > > rebased on driver-core/driver-core-next for -v6 applied bits
> > > > > (thanks)
> > > > > rework drm_debug_enabled{_raw,_instrumented,} per Dan.
> > > > >
> > > > > It excludes:
> > > > > nouveau parts (immature)
> > > > > tracefs parts (I missed --to=Steve on v6)
> > > > > split _ddebug_site and de-duplicate experiment (way unready)
> > > > >
> > > > > IOW, its the remaining commits of V6 on which Dan gave his
> > > > > Reviewed-by.
> > > > >
> > > > > If these are good to apply, I'll rebase and repost the rest
> > > > > separately.
> > > > > >>>
> > > > > >>> All now queued up, thanks.
> > > > > >>
> > > > > >> This stuff broke i915 debugs. When I first load i915 no debug
> > > > > >> prints are
> > > > > >> produced. If I then go fiddle around in
> > > > > >> /sys/module/drm/parameters/debug
> > > > > >> the debug prints start to suddenly work.
> > > > > >
> > > > > > Wait what? I always assumed the default behaviour would stay the
> > > > > > same,
> > > > > > which is usually how we roll. It's a regression in my books. We've
> > > > > > got a
> > > > > > CI farm that's not very helpful in terms of dmesg logging right now
> > > > > > because of this.
> > > > > >
> > > > > > BR,
> > > > > > Jani.
> > > > > >
> > > > > >
> > > > >
> > > > > That doesn't sound good - so you are saying that prior to this change
> > > > > some
> > > > > of the drm debugs were default enabled. But now you have to manually
> > > > > enable
> > > > > them?
> > > > >
> > > > > Thanks,
> > > > >
> > > > > -Jason
> > > >
> > > >
> > > > Im just seeing this now.
> > > > Any new details ?
> > >
> > > No. We just disabled it as BROKEN for now. I was just today thinking
> > > about sending that patch out if no solutin is forthcoming soon since
> > > we need this working before 6.1 is released.
> > >
> > > Pretty sure you should see the problem immediately with any driver
> > > (at least if it's built as a module, didn't try builtin). Or at least
> > > can't think what would make i915 any more special.
> > >
> >
> > So, I should note -
> > 99% of my time & energy on this dyndbg + drm patchset
> > has been done using virtme,
> > so my world-view (and dev-hack-test env) has been smaller, simpler
> > maybe its been fatally simplistic.
> >
> > ive just rebuilt v6.0 (before the trouble)
> > and run it thru my virtual home box,
> > I didnt see any unfamiliar drm-debug output
> > that I might have inadvertently altered somehow
> >
> > I have some real HW I can put a reference kernel on,0
> > to look for the missing output, but its all gonna take some time,
> > esp to tighten up my dev-test-env
> >
> > in the meantime, there is:
> >
> > config DRM_USE_DYNAMIC_DEBUG
> > bool "use dynamic debug to implement drm.debug"
> > default y
> > depends on DRM
> > depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
> > depends on JUMP_LABEL
> > help
> > Use dynamic-debug to avoid drm_debug_enabled() runtime overheads.
> > Due to callsite counts in DRM drivers (~4k in amdgpu) and 56
> > bytes per callsite, the .data costs can be substantial, and
> > are therefore configurable.
> >
> > Does changing the default fix things for i915 dmesg ?
>
> I think we want to mark it BROKEN in addition to make sure no one
Ok, I get the distinction now.
youre spelling that
depends on BROKEN
I have a notional explanation, and a conflating commit:
can you eliminate
git log -p ccc2b496324c13e917ef05f563626f4e7826bef1
as the cause ?
commit ccc2b496324c13e917ef05f563626f4e7826bef1
Author: Jim Cromie
Date: Sun Sep 11 23:28:51 2022 -0600
drm_print: prefer bare printk KERN_DEBUG on generic fn
drm_print.c calls pr_debug() just once, from __drm_printfn_debug(),
which is a generic/service fn. The callsite is compile-time enabled
by DEBUG in both DYNAMIC_DEBUG=y/n builds.
For dyndbg builds, reverting this callsite back to bare printk is
correcting a few anti-features:
1- callsite is generic, serves multiple drm users.
it is soft-wired on currently by #define DEBUG
could accidentally: #> echo -p > /proc/dynamic_debug/control
2- optional "decorations" by dyndbg are unhelpful/misleading here,
they describe on
