Commit 47ee4ccf authored by Adam Jackson's avatar Adam Jackson Committed by Dave Airlie
Browse files

drm/edid: Retry EDID fetch up to four times 

This matches the X server's retry logic.  Note that we'll only retry if
we get a DDC response but fail validation; legitimately disconnected
outputs will bomb out early.

See also: http://bugzilla.redhat.com/532957



Signed-off-by: default avatarAdam Jackson <ajax@redhat.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent f985dedb

drivers/gpu/drm/drm_edid.c

+14 −14
Original line number Diff line number Diff line
@@ -133,9 +133,6 @@ static bool edid_is_valid(struct edid *edid) 
		DRM_ERROR("EDID has major version %d, instead of 1\n", edid->version);

		goto bad;

	}

	if (edid->revision > 4)

		DRM_DEBUG("EDID minor > 4, assuming backward compatibility\n");



	for (i = 0; i < EDID_LENGTH; i++)

		csum += raw_edid[i];

	if (csum) {
@@ -143,6 +140,9 @@ static bool edid_is_valid(struct edid *edid) 
		goto bad;

	}



	if (edid->revision > 4)

		DRM_DEBUG("EDID minor > 4, assuming backward compatibility\n");



	return 1;



bad:
@@ -1060,19 +1060,19 @@ static int drm_ddc_read_edid(struct drm_connector *connector, 
			     struct i2c_adapter *adapter,

			     char *buf, int len)

{

	int ret;

	int i;



	ret = drm_do_probe_ddc_edid(adapter, buf, len);

	if (ret != 0) {

		goto end;

	for (i = 0; i < 4; i++) {

		if (drm_do_probe_ddc_edid(adapter, buf, len))

			return -1;

		if (edid_is_valid((struct edid *)buf))

			return 0;

	}

	if (!edid_is_valid((struct edid *)buf)) {



	/* repeated checksum failures; warn, but carry on */

	dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",

		 drm_get_connector_name(connector));

		ret = -1;

	}

end:

	return ret;

	return -1;

}



/**

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