[igt-dev] [PATCH i-g-t] i915_module_load: Unload the module before exiting the subtest

[Modem, Bhanuprakash]

On Tue-15-03-2022 07:01 pm, Petri Latvala wrote:
> On Tue, Mar 15, 2022 at 05:35:10PM +0530, Modem, Bhanuprakash wrote:
>> On Tue-15-03-2022 05:13 pm, Petri Latvala wrote:
>>> On Tue, Mar 15, 2022 at 12:25:09PM +0530, Bhanuprakash Modem wrote:
>>>> On DP-MST setup, after execution of "reload" subtest, i915
>>>> became unloadable. And this is effecting the next subtest
>>>> "reload-no-display".
>>>>
>>>> Observing below error, if we run all subtests of i915_module_load
>>>> (or) run "reload" & "reload-no-display" in same order using the
>>>> igt_runner. But not seen any issue if we run each subtest individually.
>>>>
>>>> $ ./igt_runner -o -l verbose -s --test-list tests.txt --use-watchdog ../tests/ results/
>>>> (or)
>>>> $ ./build/tests/i915_module_load
>>>>     Starting subtest: reload
>>>>     ...
>>>>     Subtest reload: SUCCESS (3.780s)
>>>>
>>>>     Starting subtest: reload-no-display
>>>>     (i915_module_load:42617) igt_kmod-WARNING: Could not unload i915
>>>>     Module                   Used by
>>>>     i915                     1
>>>>     ...
>>>>     Reloading i915 with disable_display=1
>>>>     Module i915 already inserted
>>>>     Could not load i915
>>>>     Subtest reload-no-display: FAIL (1.998s)
>>>>
>>>> $ ./build/tests/i915_module_load --r reload
>>>>     Starting subtest: reload
>>>>     ...
>>>>     Subtest reload: SUCCESS (5.562s)
>>>> $ ./build/tests/i915_module_load --r reload-no-display
>>>>     Starting subtest: reload-no-display
>>>>     ...
>>>>     Subtest reload-no-display: SUCCESS (7.995s)
>>>>
>>>> This patch will unload the module before exiting the subtest. So
>>>> that we can make sure that the module is unloaded.
>>>
>>> Does it succeed in there? Or does this just make sure that the failure
>>> is caught in the right place? What is actually holding the reference
>>> to i915.ko?
>>
>> Not sure who is holding the ref to i915. lsmod showing it is used by 1 but
>> not showing who actually holding it.
>>
>> Module                   Used by
>> i915                     1
>>
>> But with this fix, there is no such failures mentioned in commit msg.
> 
> 
> What about just having a gem_quiescent_gpu() call in there? Does that
> do anything?

I observed the same failure by using gem_quiescent_gpu() before 
unloading the module.

- Bhanu

>