[igt-dev] [PATCH i-g-t v6 21/24] tests/core_hotunplug: HSW/BDW audio issue workaround

[Petri Latvala]

On Fri, Sep 11, 2020 at 12:30:36PM +0200, Janusz Krzysztofik wrote:
> Unbinding the i915 driver on some Haswell and Broadwell platforms with
> Azalia audio results in a kernel WARNING on "i915 raw-wakerefs=1
> wakelocks=1 on cleanup".  The issue can be worked around by manually
> enabling runtime power management for the conflicting audio adapter.
> Use that method but also display a warning to preserve visibility of
> the issue.  Also tag the workaround with a FIXME comment.
> 
> v2: Extend the scope of the workaround over Broadwell
> 
> Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
> ---
>  tests/core_hotunplug.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/tests/core_hotunplug.c b/tests/core_hotunplug.c
> index ac106d964..3e2a76ddb 100644
> --- a/tests/core_hotunplug.c
> +++ b/tests/core_hotunplug.c
> @@ -484,8 +484,23 @@ igt_main
>  		igt_skip_on_f(fd_drm < 0, "No known DRM device found\n");
>  
>  		if (is_i915_device(fd_drm)) {
> +			uint32_t devid = intel_get_drm_devid(fd_drm);
> +
>  			gem_quiescent_gpu(fd_drm);
>  			igt_require_gem(fd_drm);
> +
> +			/**
> +			 * FIXME: Unbinding the i915 driver on some Haswell
> +			 * platforms with Azalia audio results in a kernel WARN
> +			 * on "i915 raw-wakerefs=1 wakelocks=1 on cleanup".  The
> +			 * below CI friendly user level workaround prevents the
> +			 * warning from appearing.  Drop this hack as soon as
> +			 * this is fixed in the kernel.
> +			 */
> +			if (igt_warn_on_f(IS_HASWELL(devid) ||
> +					  IS_BROADWELL(devid),
> +			    "Manually enabling audio PM to work around a kernel WARN\n"))
> +				igt_pm_enable_audio_runtime_pm();

What happens without this? Is it just a kernel warning, or does the
operation also fail?

If the former, what does this gain? All it does is we lose the
capability to track whether the kernel still has that issue, we still
have to filter this warning in cibuglog.


-- 
Petri Latvala