On Sat, 2009-03-21 at 04:03 +0800, Eric Anholt wrote:
> On Fri, 2009-03-20 at 15:52 +0800, Ma Ling wrote:
> > sometime we need to communicate with HDMI monitor by sending audio or video
> > info frame,
> > so we have to know the monitor type. However if user utilize HDMI->DVI
> > adapter to connect DVI monitor,
> > hardware detection will incorrectly shows the monitor is HDMI.
> > HDMI spec tell us that any device containing IEEE Registration Identifier
> > will be
> > treated HDMI device. The patch intends to detect HDMI monitor by this rule.
> >
> >
> > Any comments are welcome.
>
> Most consumers of this API will have just fetched the EDID block for
> another reason, but this code would just go and fetch it again. It
> seems like this function should probably drm_edid_block_is_hdmi(struct
> edid *edid). Or is there some problem here?
Thanks , I agree, fixed in next version.
>
> > Thanks
> > Ma Ling
> >
> > Signed-off-by: Ma Ling <ling...@intel.com>
> > ---
> > drivers/gpu/drm/drm_edid.c | 68
> > ++++++++++++++++++++++++++++++++++++++++++++
> > include/drm/drm_crtc.h | 2 +
> > 2 files changed, 70 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> > index a839a28..f92babe 100644
> > --- a/drivers/gpu/drm/drm_edid.c
> > +++ b/drivers/gpu/drm/drm_edid.c
> > @@ -677,6 +677,74 @@ struct edid *drm_get_edid(struct drm_connector
> > *connector,
> > }
> > EXPORT_SYMBOL(drm_get_edid);
> >
> > +#define HDMI_IDENTIFIER 0x000C03
> > +#define VENDOR_BLOCK 0x03
> > +/**
> > + * drm_detect_hdmi_monitor - detect whether monitor is hdmi.
> > + * @connector: connector we're probing
> > + * @adapter: i2c adapter to use for DDC
> > + *
> > + * Parse the CEA extension according to CEA-861-B.
> > + * Return true if HDMI, false if not or unknown.
> > + */
> > +bool drm_detect_hdmi_monitor(struct drm_connector *connector,
> > + struct i2c_adapter *adapter)
> > +{
> > + struct edid *edid;
> > + char *edid_ext = NULL;
> > + int start_offset, end_offset;
> > + int i, hdmi_id;
> > + bool ret = false;
>
> since ret isn't "0 for success, -ESOMETHING for failure", could it get
> renamed to "is_hdmi" or something?
fixed.
>
> > +
> > + edid = drm_get_edid(connector, adapter);
> > +
> > + /* No EDID or EDID extensions */
> > + if (edid == NULL || edid->extensions == 0)
> > + goto end;
> > +
> > + /* Find CEA extension */
> > + for (i = 0; i < edid->extensions; i++) {
> > + edid_ext = (char *)edid + EDID_LENGTH * (i + 1);
> > + /* This block is CEA extension */
> > + if (edid_ext[0] == 0x02)
> > + break;
> > + }
> > +
> > + if (i == edid->extensions)
> > + goto end;
> > +
> > + /* Data block offset in CEA extension block */
> > + start_offset = 4;
> > + end_offset = edid_ext[2];
> > +
> > + /*
> > + * Because HDMI identifier is in Vendor Specific Block,
> > + * search it from all data blocks of CEA extension.
> > + */
> > + for (i = start_offset; i < end_offset;
> > + /* Increased by data block len */
> > + i += ((edid_ext[i] & 0x1f) + 1)) {
>
> indentation alignment
fixed.
>
> > + /* Find vendor specific block */
> > + if ((edid_ext[i] >> 5) == VENDOR_BLOCK) {
> > + hdmi_id = edid_ext[i + 1] | (edid_ext[i + 2] << 8) |
> > + edid_ext[i + 3] << 16;
> > + /* Find HDMI identifier */
> > + if (hdmi_id == HDMI_IDENTIFIER)
> > + ret = true;
> > + break;
> > + }
> > + }
> > +
> > +end:
> > + if (edid != NULL) {
> > + connector->display_info.raw_edid = NULL;
> > + kfree(edid);
> > + }
> > +
> > + return ret;
> > +}
> > +EXPORT_SYMBOL(drm_detect_hdmi_monitor);
> > +
> > /**
> > * drm_add_edid_modes - add modes from EDID data, if available
> > * @connector: connector we're probing
> > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> > index 5ded1ac..e578f55 100644
> > --- a/include/drm/drm_crtc.h
> > +++ b/include/drm/drm_crtc.h
> > @@ -731,4 +731,6 @@ extern int drm_mode_gamma_get_ioctl(struct drm_device
> > *dev,
> > void *data, struct drm_file *file_priv);
> > extern int drm_mode_gamma_set_ioctl(struct drm_device *dev,
> > void *data, struct drm_file *file_priv);
> > +extern bool drm_detect_hdmi_monitor(struct drm_connector *connector,
> > + struct i2c_adapter *adapter);
> > #endif /* __DRM_CRTC_H__ */
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