[Lets see if I have a working vpn connection today...]
On Sun, 19 Sep 2010 14:52:06 +0800, Zhenyu Wang zhenyuw@linux.intel.com wrote:
To help to determine if digital display port needs to enable audio output or not. This one adds a helper to get monitor's audio capability via EDID CEA extension block.
Tested-by: Wu Fengguang fengguang.wu@intel.com Signed-off-by: Zhenyu Wang zhenyuw@linux.intel.com
This should be cc'ed for Adam Jackson's attention as well.
drivers/gpu/drm/drm_edid.c | 92 +++++++++++++++++++++++++++++++++++++------- include/drm/drm_crtc.h | 1 + 2 files changed, 79 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 96e9631..7f356af 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -1268,34 +1268,51 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid, }
#define HDMI_IDENTIFIER 0x000C03 +#define AUDIO_BLOCK 0x01 #define VENDOR_BLOCK 0x03 +#define EDID_BASIC_AUDIO (1 << 6)
/**
- drm_detect_monitor_audio - check monitor audio capability
- Monitor should have CEA extension block.
- If monitor has 'basic audio', but no CEA audio blocks, it's 'basic
- audio' only. If there is any audio extension block and supported
- audio format, assume at least 'basic audio' support, even if 'basic
- audio' is not defined in EDID.
- */
+bool drm_detect_monitor_audio(struct edid *edid)
drm_edid_has_monitor_audio()? That is a little more self-descriptive. (I also think drm_detect_hdmi_monitor is poorly named.)
+{
- u8 *edid_ext;
- int i, j;
- bool has_audio = false;
- int start_offset, end_offset;
- edid_ext = drm_find_cea_extension(edid);
- if (!edid_ext)
goto end;- has_audio = ((edid_ext[3] & EDID_BASIC_AUDIO) != 0);
Too many brackets do not lead to code clarity. ;-)
- if (has_audio) {
The last time Adam had a chance to comment on this EDID check, he suggested that we cannot rely on has_audio being a reliable indicator of the sink's properties. If the EDID has no audio support, then return early, otherwise perform the secondary check that extension block contains audio data. -Chris