Hi,

On 22-02-18 12:08, Takashi Iwai wrote:

On Thu, 22 Feb 2018 11:53:51 +0100, Hans de Goede wrote:

...

Hi All,

On some boards setting power_save to a non 0 value leads to clicking / popping sounds when ever we enter/leave powersaving mode. Ideally we would figure out how to avoid these sounds, but that is not always feasible.

This commit adds a blacklist for devices where powersaving is known to cause problems and disables it on these devices.

Note this patch ATM is a RFC because I still need to get test-feedback that it actually works on affected boards.

I tried to put this blacklist in userspace first: https://github.com/systemd/systemd/pull/8128

But the systemd maintainers rightfully pointed out that it would be impossible to then later remove entries once we actually find a way to make power-saving work on listed boards without issues. Having this list in the kernel will allow removal of the blacklist entry in the same commit which fixes the clicks / plops.

I've chosen to also apply the blacklist to changes made through /sys/module/snd_hda_intel/parameters/power_save, since tools such as powertop and TLP do this automatically.

About the choice to also apply this to changes made through /sys/module/snd_hda_intel/parameters/power_save, one could argue that this will get in the way of users who want the power-saving anyways and are willing to live with the clicks/plops. An alternative approach would be to only apply this to the value of the module-parameter at boot and then only when it matches CONFIG_SND_HDA_POWER_SAVE_DEFAULT. I'm open to changing this.

IMO, we shouldn't prevent user to set the explicit power_save mode even if it's blacklisted. That is, if any, I prefer blacklist influencing only on the default value, a patch like below.

Ok, luckily I've not yet started a test-kernel build for people to test, so I will rework this as you suggest and then do the test-build.

But, before adding to the blacklist, it's better to investigate the cause.

I completely agree, but with power_save defaulting to 1 in the upcoming Fedora 28 I'm not sure we will have time to fully investigate every issue, also not every reporter may have the time to work with us on this, I still have one bugreport open where I'm waiting for "lspci -v -nn" output...

I see this blacklist as a way to give people a working config / fix regressions quickly, as said already I completely agree that actually fixing things is better. I'm just not sure that is feasible in all cases.

For example, Lenovo X1 is definitely a thing to be looked at. Often a simple turn-off of "Loopback Mixing" element is enough.

Hmm, we've already tried several of the quirks from patch_realtek.c on this one, but they have not helped. Another member of my team has access to one and is more then happy to test better fixes, see: https://bugzilla.kernel.org/show_bug.cgi?id=198611

So if you've anything he can try to fix this please leave a comment there.

We need alsa-info.sh output for further investigation for each case, in anyway.

Ok, note I've added a bugzilla link to each blacklist entry exactly so that we can follow up and try to come up with a better fix.

I will ask all reporters to run alsa-info.sh and attach the generated file to the bugs.

Regards,

Hans

thanks,

Takashi

===

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index c71dcacea807..f21bf0add9f0 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -181,7 +181,7 @@ static const struct kernel_param_ops param_ops_xint = { }; #define param_check_xint param_check_int

-static int power_save = CONFIG_SND_HDA_POWER_SAVE_DEFAULT; +static int power_save = -1; /* default */ module_param(power_save, xint, 0644); MODULE_PARM_DESC(power_save, "Automatic power-saving timeout " "(in second, 0 = disable)."); @@ -2198,6 +2198,7 @@ static int azx_probe_continue(struct azx *chip) struct hdac_bus *bus = azx_bus(chip); struct pci_dev *pci = chip->pci; int dev = chip->dev_index;

• int val; int err;

  hda->probe_continued = 1;

@@ -2278,7 +2279,11 @@ static int azx_probe_continue(struct azx *chip)

chip->running = 1; azx_add_card_list(chip);

• snd_hda_set_power_save(&chip->bus, power_save * 1000);

• val = power_save;
• if (val < 0 && !is_power_save_blacklisted(chip))

• val = CONFIG_SND_HDA_POWER_SAVE_DEFAULT;
  

• if (val >= 0)

• snd_hda_set_power_save(&chip->bus, val * 1000);
  

  if (azx_has_pm_runtime(chip) || hda->use_vga_switcheroo) pm_runtime_put_autosuspend(&pci->dev);