ALSA : hda - bug fix on checking the supported power states of a codec
The return value of snd_hda_param_read() is -1 for an error, otherwise
it's the supported power states of a codec.
The supported power states is a 32-bit value. Bit 31 will be set to 1
if the codec supports EPSS, thus making "sup" negative. And the bit
28:5 is reserved as "0".
So a negative value other than -1 shall be further checked.
Please refer to High-Definition spec 7.3.4.12 "Supported Power
States", thanks!
Signed-off-by: Mengdong Lin <mengdong.lin@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 88a9c20..629131a 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -3497,7 +3497,7 @@
{
int sup = snd_hda_param_read(codec, fg, AC_PAR_POWER_STATE);
- if (sup < 0)
+ if (sup == -1)
return false;
if (sup & power_state)
return true;