[alsa-devel] [PATCH v2] ALSA: Fix mute led GPIO on HP dv-series notebooks.

Kunal Gangakhedkar kunal.gangakhedkar at gmail.com
Fri Jan 15 14:32:17 CET 2010

On Friday 15 Jan 2010 6:51:30 pm Takashi Iwai wrote:
> At Fri, 15 Jan 2010 18:35:19 +0530,
> Kunal Gangakhedkar wrote:
> > 
> > On my laptop (HP dv6-1110ax), there are no OEM strings in SMBIOS of type
> > "HP_Mute_LED*". Hence, the GPIO for the mute button LED doesn't get set
> > properly. I didn't find the strings in my cousin's laptop (HP dv9500t CTO)
> > either.
> > 
> > As per the documentation of find_mute_led_gpio(), these strings occur
> > in HP B-series systems - so, before scanning the SMBIOS strings, we need to
> > check if we're dealing with a B-series system.
> > Need to get confirmation from HP if this logic takes care of all the
> > systems. I'm trying to poke a friend there.
> > 
> > Please let me know if this looks OK or needs changes.
> Well, the open switch() for blike-system should be replaced with
> set_hp_led_gpio().  That's the very purpose I proposed to create a
> function.

I don't think you can do that since both cases (b-like and non-b-like) have
different ways of setting the gpio. 

> Thinking the logic again, however, it might be safer to check DMI
> entries no matter which model is.  Then set statically if it's DV
> series (i.e. !hp_blike_system()) as fallback.  I suppose HP will
> implement the DMI entry for their new BIOS on other models in future,
> too, so the chance is high that the right setup is detected through
> DMI check instead of blindly fixed setup.

They're notorious to discontinue models really fast. For example, my laptop model
is already discontinued in less than 6 months. So, I don't think I'll be getting updates
for my BIOS at all. What do you propose for such cases?

I agree with your approach that we should be checking for DMI string unconditionally and 
use the fixed setup as fallback - I can send the patch with those fixes too.
Let me know if that's what you'd prefer.


> thanks,
> Takashi
> > 

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