Hi, all I'm an Nvidia engineer, I maintain the nvidia linux hdmi audio driver.
An end-user report a problem with his TV attached to an MCP89. ALSA won't send audio to it, because PD=3D0: HDMI hot plug event: Pin=3D5 Presence_Detect=3D1 ELD_Valid=3D0 HDMI hot plug event: Pin=3D5 Presence_Detect=3D0 ELD_Valid=3D1
As you know, in linux driver patch_hdmi.c, it use (pind && eldv) in unsolicited events. So the driver can't detect the monitor.
_From the HAD specification (http://download.intel.com/standards/hdaudio/pdf/HDA036.pdf):
Original text for Unsolicited Response PD bit:
Presence Detect: When this bit is set, sense measurement has changed on the pin widget and software can use the pin sense control verb to determine the current pin sense data state. For analog pin widgets, this UR means that Presence Detect or Impedance has changed on the pin widget. For digital pin widgets, including HDMI pin widgets, this means that presence detect (and optionally ELD valid bit) has **changed**. [my emphasis]
Updated text for Unsolicted Response PD bit:
Presence Detect: This bit reflects the **present** [my emphasis] state of the Pin Sense Presence Detect bit when the unsolicited response is triggered. Software can optionally use the pin sense control verb to determine the latest pin sense data state. This bit implementation is only required for digital display pin widget. Non digital display pin widget is optional to implement this bit.
For our MCP89, the values indicates the change of status of PD, not the a= ctual value of PD, which follows older description of UR for PD bit.
So could we add a workaround for MCP89? We could use Pin Sense to determi= ne again in unsolicited events. If it return 0xc0000000, it means PD=3D1 and ELVD=3D1= . Or do you have any suggestions?
Thanks Wei.
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