| Message ID | 20221111221715.563020-2-jim.cromie@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | DYNAMIC_DEBUG fixups for rc | expand |
On Fri, Nov 11, 2022 at 03:17:09PM -0700, Jim Cromie wrote: > drm.debug-on-dyndbg has a regression, due to a chicken-egg > initialization problem: > > 1- modprobe i915 > i915 needs drm.ko, which is loaded 1st > > 2- "modprobe drm drm.debug=0x1ff" (virtual/implied) > drm.debug is set post-initialization, from boot-args etc > > 3- `modprobe i915` finishes > > W/O drm.debug-on-dyndbg that just works, because all drm_dbg* > callsites use drm_debug_enabled() to check __drm_debug & DEM_UT_<CAT> > before printing. > > But the whole point of drm.debug-on-dyndbg is to avoid that runtime > test, by enabling (at post-modinit) a static-key at each callsite in > the just-loaded module. > > And since drm.ko is loaded before all dependent modules, none are > "just-loaded", and no drm.debug callsites are present yet, except > those in drm.ko itself. > > Signed-off-by: Jim Cromie <jim.cromie@gmail.com> > --- > drivers/gpu/drm/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index 34f5a092c99e..0d1e59e6bb7e 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -54,6 +54,7 @@ config DRM_DEBUG_MM > config DRM_USE_DYNAMIC_DEBUG > bool "use dynamic debug to implement drm.debug" > default y Could you switch to 'default n' as well? i915 CI actually enables BROKEN so that we can test some more experimental stuff which is hidden behind BROKEN for normal users. > + depends on BROKEN # chicken-egg initial enable problem > depends on DRM > depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE > depends on JUMP_LABEL > -- > 2.38.1
On Fri, Nov 11, 2022 at 03:17:09PM -0700, Jim Cromie wrote: > drm.debug-on-dyndbg has a regression, due to a chicken-egg > initialization problem: > > 1- modprobe i915 > i915 needs drm.ko, which is loaded 1st > > 2- "modprobe drm drm.debug=0x1ff" (virtual/implied) > drm.debug is set post-initialization, from boot-args etc > > 3- `modprobe i915` finishes > > W/O drm.debug-on-dyndbg that just works, because all drm_dbg* > callsites use drm_debug_enabled() to check __drm_debug & DEM_UT_<CAT> > before printing. > > But the whole point of drm.debug-on-dyndbg is to avoid that runtime > test, by enabling (at post-modinit) a static-key at each callsite in > the just-loaded module. > > And since drm.ko is loaded before all dependent modules, none are > "just-loaded", and no drm.debug callsites are present yet, except > those in drm.ko itself. > > Signed-off-by: Jim Cromie <jim.cromie@gmail.com> > --- > drivers/gpu/drm/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index 34f5a092c99e..0d1e59e6bb7e 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -54,6 +54,7 @@ config DRM_DEBUG_MM > config DRM_USE_DYNAMIC_DEBUG > bool "use dynamic debug to implement drm.debug" > default y > + depends on BROKEN # chicken-egg initial enable problem > depends on DRM > depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE > depends on JUMP_LABEL > -- > 2.38.1 This should go through the drm tree now. The rest probably should also go that way and not through my tree as well. thanks, greg k-h
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 34f5a092c99e..0d1e59e6bb7e 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -54,6 +54,7 @@ config DRM_DEBUG_MM config DRM_USE_DYNAMIC_DEBUG bool "use dynamic debug to implement drm.debug" default y + depends on BROKEN # chicken-egg initial enable problem depends on DRM depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE depends on JUMP_LABEL
drm.debug-on-dyndbg has a regression, due to a chicken-egg initialization problem: 1- modprobe i915 i915 needs drm.ko, which is loaded 1st 2- "modprobe drm drm.debug=0x1ff" (virtual/implied) drm.debug is set post-initialization, from boot-args etc 3- `modprobe i915` finishes W/O drm.debug-on-dyndbg that just works, because all drm_dbg* callsites use drm_debug_enabled() to check __drm_debug & DEM_UT_<CAT> before printing. But the whole point of drm.debug-on-dyndbg is to avoid that runtime test, by enabling (at post-modinit) a static-key at each callsite in the just-loaded module. And since drm.ko is loaded before all dependent modules, none are "just-loaded", and no drm.debug callsites are present yet, except those in drm.ko itself. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- drivers/gpu/drm/Kconfig | 1 + 1 file changed, 1 insertion(+)