[alsa-devel] [PATCH] ALSA: hda: invert mute led polarity for HP laptops

Gustavo Maciel Dias Vieira gustavo at sagui.org
Mon Dec 12 17:07:50 CET 2011

Em Seg, 2011-12-12 às 15:04 +0100, Takashi Iwai escreveu:
> At Mon, 12 Dec 2011 11:55:59 -0200,
> Gustavo Maciel Dias Vieira wrote:
> > Unfortunately no. Actually, it appears someone at HP is pulling a
> prank
> > on us. In a Pavilion dm4 the BIOS string is "HP_Mute_LED_P_G", where
> P
> > and G are not numbers, but the actual letters.
> Doh, they forgot to fill the right numbers there.  Obviously a BIOS
> bug.
> For such machines, the IDs should be explicitly checked instead of
> marking all machines with this codec.  That is, the influence must be
> as small as possible.  Or, just check "HP_Mute_LED_P_G" string as an
> identifier of bad machines, and apply a special handling.

I can do both, to be double sure. Just tell me which ID to use. I
assumed that codec->subsystem_id was unique enough (by inspecting

> BTW, now IDT guys and I are discussing about dropping the fallback
> case for 92HD83x codecs because it can break potentially the EAPD.
> Your patch won't work any more if that change is applied.  So, a more
> solid fix would be needed anyway.

It's a BIOS bug. Any fix is going to suck. :)


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