[alsa-devel] Changing snd_hda_intel.power_save default value ?
Hi All,
I'm working on trying to improve the OOTB power-consumption of Linux (Fedora Workstation) on laptops.
One of the easy wins here is setting snd_hda_intel.power_save=1
I see that the default is configurable through a Kconfig option, currently Fedora is using the Kconfig default value of 0.
So I'm wondering if there any known issues with changing the default to 1 ?
I was also thinking that maybe an automatic value (SND_HDA_POWER_SAVE_DEFAULT == -1) might be a good idea, which would mean 0 normally except for PCI-ids which are markes with a MOBILE flag in their driver_data in the azx_ids pci_device_id table ?
Regards,
Hans
On Wed, 01 Nov 2017 15:19:44 +0100, Hans de Goede wrote:
Hi All,
I'm working on trying to improve the OOTB power-consumption of Linux (Fedora Workstation) on laptops.
One of the easy wins here is setting snd_hda_intel.power_save=1
I see that the default is configurable through a Kconfig option, currently Fedora is using the Kconfig default value of 0.
So I'm wondering if there any known issues with changing the default to 1 ?
This may bring click noises on some laptops or desktops, but it should be OK for the functionalities. On openSUSE Tumbleweed kernels, we already pass 1 for some time. Some reports came up occasionally but they can work around by setting the module option.
I was also thinking that maybe an automatic value (SND_HDA_POWER_SAVE_DEFAULT == -1) might be a good idea, which would mean 0 normally except for PCI-ids which are markes with a MOBILE flag in their driver_data in the azx_ids pci_device_id table ?
I'm afraid that it'd be hard to manage that table. This is one of mostly modified module option, e.g. a power-management daemon often adjusts the value dynamically. So, for modern distros, feel free simply set to value 1, but I see no reason to hustle for changing kconfig default value in the tree. For the default value, we want to be conservative in general.
thanks,
Takashi
Hi,
On 01-11-17 17:54, Takashi Iwai wrote:
On Wed, 01 Nov 2017 15:19:44 +0100, Hans de Goede wrote:
Hi All,
I'm working on trying to improve the OOTB power-consumption of Linux (Fedora Workstation) on laptops.
One of the easy wins here is setting snd_hda_intel.power_save=1
I see that the default is configurable through a Kconfig option, currently Fedora is using the Kconfig default value of 0.
So I'm wondering if there any known issues with changing the default to 1 ?
This may bring click noises on some laptops or desktops, but it should be OK for the functionalities. On openSUSE Tumbleweed kernels, we already pass 1 for some time. Some reports came up occasionally but they can work around by setting the module option.
I was also thinking that maybe an automatic value (SND_HDA_POWER_SAVE_DEFAULT == -1) might be a good idea, which would mean 0 normally except for PCI-ids which are markes with a MOBILE flag in their driver_data in the azx_ids pci_device_id table ?
I'm afraid that it'd be hard to manage that table. This is one of mostly modified module option, e.g. a power-management daemon often adjusts the value dynamically. So, for modern distros, feel free simply set to value 1, but I see no reason to hustle for changing kconfig default value in the tree. For the default value, we want to be conservative in general.
Ok, I will discuss changing the Kconfig option to "1" with the Fedora kernel team.
Thanks & Regards,
Hans
participants (2)
-
Hans de Goede -
Takashi Iwai