On Mon, Sep 6, 2021 at 6:26 AM Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx> wrote:
>
>
> On 03/09/2021 20:22, jim.cromie@xxxxxxxxx wrote:
> > On Fri, Sep 3, 2021 at 5:07 AM Tvrtko Ursulin
> > <tvrtko.ursulin@xxxxxxxxxxxxxxx> wrote:
> >>
> >>
> >> On 31/08/2021 21:21, Jim Cromie wrote:
> >>> The gvt component of this driver has ~120 pr_debugs, in 9 categories
> >>> quite similar to those in DRM. Following the interface model of
> >>> drm.debug, add a parameter to map bits to these categorizations.
> >>>
> >>> DEFINE_DYNAMIC_DEBUG_CATEGORIES(debug_gvt, __gvt_debug,
> >>> "dyndbg bitmap desc",
> >>> { "gvt:cmd: ", "command processing" },
> >>> v7:
> >>> . move ccflags addition up to i915/Makefile from i915/gvt
> >>> ---
> >>> drivers/gpu/drm/i915/Makefile | 4 ++++
> >>> drivers/gpu/drm/i915/i915_params.c | 35 ++++++++++++++++++++++++++++++
> >>
> >> Can this work if put under gvt/ or at least intel_gvt.h|c?
I tried this.
I moved the code block into gvt/debug.c (new file)
added it to Makefile GVT_SOURCES
dunno why it wont make.
frustratig basic err, Im not seeing.
It does seem proper placement, will resolve...
> >>
> >
> > I thought it belonged here more, at least according to the name of the
> > config.var
>
> Hmm bear with me please - the categories this patch creates are intended
> to be used explicitly from the GVT "sub-module", or they somehow even
> get automatically used with no further intervention to callers required?
>
2009 - v5.9.0 the only users were admins reading/echoing /proc/dynamic_debug/control
presumably cuz they wanted more info in the logs, episodically.
v5.9.0 exported dynamic_debug_exec_queries for in-kernel use,
reusing the stringy: echo $query_command > control idiom.
My intention was to let in-kernel users roll their own drm.debug type interface,
or whatever else they needed. nobodys using it yet.
patch 1/8 implements that drm.debug interface.
5/8 is the primary use case
3/8 (this patch) & 4/8 are patches of opportunity, test cases, proof of function/utility.
its value as such is easier control of those pr-debugs than given by echo > control
Sean Paul seanpaul@xxxxxxxxxxxx worked up a patchset to do runtime steering of drm-debug stream,
in particular watching for drm:atomic:fail: type activity (a subcategory which doesnt exist yet).
5/8 conflicts with his patchset, I have an rfc approach to that, so his concerns are mine too.
note: if this patchset goes in, we dont *really* need the export anymore,
since the main use case is covered. We could un-export, and re-add later
if its needed for a different use case. Further, it seems likely that the callbacks
(refactored) would be a better basis for new in-kernel users.
If not that, then full exposure of struct ddebug_query to in-kernel use
On Mon, Sep 6, 2021 at 6:26 AM Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx> wrote:
On 03/09/2021 20:22, jim.cromie@xxxxxxxxx wrote:
> On Fri, Sep 3, 2021 at 5:07 AM Tvrtko Ursulin
> <tvrtko.ursulin@xxxxxxxxxxxxxxx> wrote:
>>
>>
>> On 31/08/2021 21:21, Jim Cromie wrote:
>>> The gvt component of this driver has ~120 pr_debugs, in 9 categories
>>> quite similar to those in DRM. Following the interface model of
>>> drm.debug, add a parameter to map bits to these categorizations.
>>>
>>> DEFINE_DYNAMIC_DEBUG_CATEGORIES(debug_gvt, __gvt_debug,
>>> "dyndbg bitmap desc",
>>> { "gvt:cmd: ", "command processing" },
>>> { "gvt:core: ", "core help" },
>>> { "gvt:dpy: ", "display help" },
>>> { "gvt:el: ", "help" },
>>> { "gvt:irq: ", "help" },
>>> { "gvt:mm: ", "help" },
>>> { "gvt:mmio: ", "help" },
>>> { "gvt:render: ", "help" },
>>> { "gvt:sched: " "help" });
>>>
>
> BTW, Ive dropped the help field, its already handled, dont need to clutter.
>
>
>>> The actual patch has a few details different, cmd_help() macro emits
>>> the initialization construct.
>>>
>>> if CONFIG_DRM_USE_DYNAMIC_DEBUG, then -DDYNAMIC_DEBUG_MODULE is added
>>> cflags, by gvt/Makefile.
>>>
>>> Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>
>>> ---
>>> v5:
>>> . static decl of vector of bit->class descriptors - Emil.V
>>> . relocate gvt-makefile chunk from elsewhere
>>> v7:
>>> . move ccflags addition up to i915/Makefile from i915/gvt
>>> ---
>>> drivers/gpu/drm/i915/Makefile | 4 ++++
>>> drivers/gpu/drm/i915/i915_params.c | 35 ++++++++++++++++++++++++++++++
>>
>> Can this work if put under gvt/ or at least intel_gvt.h|c?
>>
>
> I thought it belonged here more, at least according to the name of the
> config.var
Hmm bear with me please - the categories this patch creates are intended
to be used explicitly from the GVT "sub-module", or they somehow even
get automatically used with no further intervention to callers required?
> CONFIG_DRM_USE_DYNAMIC_DEBUG.
>
> I suppose its not a great name, its narrow purpose is to swap
> drm-debug api to use dyndbg. drm-evrything already "uses"
> dyndbg if CONFIG_DYNAMIC_DEBUG=y, those gvt/pr_debugs in particular.
>
> Theres also CONFIG_DYNAMIC_DEBUG_CORE=y,
> which drm basically ignores currently.
>
> So with the name CONFIG_DRM_USE_DYNAMIC_DEBUG
> it seemed proper to arrange for that to be true on DD-CORE=y builds,
> by adding -DDYNAMIC_DEBUG_MODULE
>
> Does that make some sense ?
> How to best resolve the frictions ?
> new CONFIG names ?
>
>>> 2 files changed, 39 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
>>> index 4f22cac1c49b..5a4e371a3ec2 100644
>>> --- a/drivers/gpu/drm/i915/Makefile
>>> +++ b/drivers/gpu/drm/i915/Makefile
>>> @@ -30,6 +30,10 @@ CFLAGS_display/intel_fbdev.o = $(call cc-disable-warning, override-init)
>>>
>>> subdir-ccflags-y += -I$(srctree)/$(src)
>>>
>>> +#ifdef CONFIG_DRM_USE_DYNAMIC_DEBUG
>>> +ccflags-y += -DDYNAMIC_DEBUG_MODULE
>>> +#endif
>>
>> Ignores whether CONFIG_DRM_I915_GVT is enabled or not?
>>
>
> not intentionally.
> I think theres 2 things youre noting:
>
> 1 - make frag into gvt/Makefile
> I had it there earlier, not sure why I moved it up.
> maybe some confusion on proper scope of the flag.
>
>
> 2 - move new declaration code in i915-param.c inside the gvt ifdef
>
> Im good with that.
> I'll probably copy the ifdef wrapper down rather than move the decl up.
> ie:
>
> #if __and(IS_ENABLED(CONFIG_DRM_I915_GVT),
> IS_ENABLED(CONFIG_DRM_USE_DYNAMIC_DEBUG))
>
> unsigned long __gvt_debug;
> EXPORT_SYMBOL(__gvt_debug);
>
>
>>> +
>>> # Please keep these build lists sorted!
>>>
>>> # core driver code
>>> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
>>> index e07f4cfea63a..e645e149485e 100644
>>> --- a/drivers/gpu/drm/i915/i915_params.c
>>> +++ b/drivers/gpu/drm/i915/i915_params.c
>>> @@ -265,3 +265,38 @@ void i915_params_free(struct i915_params *params)
>>> + _DD_cat_("gvt:mmio:"),
>>> + _DD_cat_("gvt:render:"),
>>> + _DD_cat_("gvt:sched:"));
>>> +
>>> +#endif
>>
>> So just the foundation - no actual use sites I mean? How would these be
>> used from the code?
>>
>
> there are 120 pr_debug "users" :-)
>
> no users per se, but anyone using drm.debug
> /sys/module/drm/parameters/debug
> might use this too.
> its a bit easier than composing queries for >/proc/dyamic_debug/control
Same as my previous question, perhaps I am not up to speed with this
yet.. Even if pr_debug is used inside GVT - are the categories and
debug_gvt global as of this patch (or series)?
they are already global in the sense that if kernel is built with DYNAMIC_DEBUG,
the admin can turn those pr_debugs on and off, and change their decorations in the log (mod,func.line).
Nor are modules protected from each other; drm-core could use dd-exec-queries to enable/disable
pr-debugs in i915 etc
This patch just adds a gvt-debug knob like drm-debug. using the existing format prefixes to categorize them.
Whether those prefixes should be bent towards consistency with the rest of drm-debug
or adapted towards some gvt community need I couldnt say.
Its no save-the-world feature, but its pretty cheap.
Id expect the same users as those who play with drm.debug, for similar reasons.
does this clarify ?
Regards,
Tvrtko
thanks,
Jim
