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);
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