On Thu, Aug 16, 2018 at 07:01:36PM +0100, Chris Wilson wrote:
> Loading the sounds modules is asynchronous with the sysfs device
> hierarchy being instantiated sometime after modprobe returns. As such
> while we are probing for the sound device, poll a few times to
> accommodate the async discovery.
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Imre Deak <imre.deak@xxxxxxxxx>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
> ---
> lib/igt_pm.c | 65 +++++++++++++++++++++++++++++++++-------------------
> 1 file changed, 41 insertions(+), 24 deletions(-)
>
> diff --git a/lib/igt_pm.c b/lib/igt_pm.c
> index 6e96db22b..f82707231 100644
> --- a/lib/igt_pm.c
> +++ b/lib/igt_pm.c
> @@ -138,31 +138,17 @@ static void strchomp(char *str)
> str[len - 1] = 0;
> }
>
> -/**
> - * igt_pm_enable_audio_runtime_pm:
> - *
> - * We know that if we don't enable audio runtime PM, snd_hda_intel will never
> - * release its power well refcount, and we'll never reach the LPSP state.
> - * There's no guarantee that it will release the power well if we enable
> - * runtime PM, but at least we can try.
> - *
> - * We don't have any assertions on open since the user may not even have
> - * snd_hda_intel loaded, which is not a problem.
> - */
> -void igt_pm_enable_audio_runtime_pm(void)
> +static int __igt_pm_enable_audio_runtime_pm(void)
> {
> char *path = NULL;
> struct dirent *de;
> DIR *dir;
> + int err;
> int fd;
>
> - /* Check if already enabled. */
> - if (__igt_pm_audio_runtime_power_save[0])
> - return;
> -
> dir = opendir("/sys/class/sound");
> if (!dir)
> - return;
> + return 0;
>
> /* Find PCI device claimed by snd_hda_intel and tied to i915. */
> while ((de = readdir(dir))) {
> @@ -196,18 +182,17 @@ void igt_pm_enable_audio_runtime_pm(void)
> de->d_name));
>
> igt_debug("Audio device path is %s\n", path);
> -
> break;
> }
Could close dir while at it.
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
This time the catch was that snd_hda_intel's second half of probe is run
from a scheduled work. (even though the first half returns synchronously
due to modprobe being synchronous as you found last time)
>
> fd = open("/sys/module/snd_hda_intel/parameters/power_save", O_RDWR);
> if (fd < 0)
> - return;
> + return 0;
>
> /* snd_hda_intel loaded but no path found is an error. */
> if (!path) {
> close(fd);
> - errno = ESRCH;
> + err = -ESRCH;
> goto err;
> }
>
> @@ -219,8 +204,10 @@ void igt_pm_enable_audio_runtime_pm(void)
> close(fd);
>
> fd = open(path, O_RDWR);
> - if (fd < 0)
> + if (fd < 0) {
> + err = -errno;
> goto err;
> + }
>
> igt_assert(read(fd, __igt_pm_audio_runtime_control,
> sizeof(__igt_pm_audio_runtime_control)) > 0);
> @@ -236,12 +223,42 @@ void igt_pm_enable_audio_runtime_pm(void)
>
> /* Give some time for it to react. */
> sleep(1);
> -
> - return;
> + return 0;
>
> err:
> - igt_warn("Failed to enable audio runtime PM! (%d)", errno);
> free(path);
> + return err;
> +}
> +
> +/**
> + * igt_pm_enable_audio_runtime_pm:
> + *
> + * We know that if we don't enable audio runtime PM, snd_hda_intel will never
> + * release its power well refcount, and we'll never reach the LPSP state.
> + * There's no guarantee that it will release the power well if we enable
> + * runtime PM, but at least we can try.
> + *
> + * We don't have any assertions on open since the user may not even have
> + * snd_hda_intel loaded, which is not a problem.
> + */
> +void igt_pm_enable_audio_runtime_pm(void)
> +{
> + int err;
> +
> + /* Check if already enabled. */
> + if (__igt_pm_audio_runtime_power_save[0])
> + return;
> +
> + for (int count = 0; count < 5; count++) {
> + err = __igt_pm_enable_audio_runtime_pm();
> + if (!err)
> + return;
> +
> + /* modprobe(sna-hda-intel) is async so poll for sysfs */
> + sleep(1);
> + }
> +
> + igt_warn("Failed to enable audio runtime PM! (%d)\n", -err);
> }
>
> /**
> --
> 2.18.0
>
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