On Tue, 29 Aug 2023 16:18:12 +0200,We spoke to the ODM for this system to get a more detailed explanation of this feature.
Stefan Binding wrote:
It's still the question whether we have to do this inevitably in the
On 25/08/2023 13:13, Takashi Iwai wrote:
On Fri, 25 Aug 2023 14:05:25 +0200,This feature is not the "normal" mute button on a keyboard, it is a
Stefan Binding wrote:
From: Vitaly Rodionov <vitalyr@xxxxxxxxxxxxxxxxxxxxx>We don't do normally in this way. The ACPI hot key handling is done
Some laptops require a hardware based mute system, where when a hotkey
is pressed, it forces the amp to be muted.
For CS35L41, when the hotkey is pressed, an acpi notification is sent
to the CS35L41 Device Node. The driver needs to handle this notification
and call a _DSM function to retrieve the mute state.
Since the amp is only muted during playback, the driver will only mute
or unmute if playback is occurring, otherwise it will save the mute
state for when playback starts.
Only one handler can be registered for the acpi notification, but all
amps need to receive that notification, we can register a single handler
inside the Realtek HDA driver, so that it can then notify through the
component framework.
Signed-off-by: Vitaly Rodionov <vitalyr@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx>
via user-space, and user-space daemon triggers the mute of the
system.
Can't the ACPI notify the key event on those machines?
custom request
from a manufacturer which only mutes the audio on the speakers.
On previous generations, this was achieved using a GPIO controlled by
the BIOS/EC.
However, since CS35L41 does not have such GPIO, we must control it by
other means.
Our solution, which we have to share with the Windows driver, it to use ACPI
notifications to tell the driver to mute the amps when the shortcut is
pressed.
Does this seem like a valid exception to the typical approach?
kernel in a way like that. It sounds quite unusual. Why this must be
handled directly? IOW, what's the difference from the "normal" mute
button?
And, even if we take this approach, it leaves the device muted without
exposing it to user-space. Then user wouldn't know what happens.
thanks,
Takashi