From f1a2f5b7c5f0941d23eef0a095c0b99bf8d051e6 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Mon, 13 Aug 2012 13:22:35 +0300 Subject: [PATCH] drm/i915: fall back to bit-banging if GMBUS fails in CRT EDID reads GMBUS was enabled over bit-banging as the default in commits: commit c3dfefa0a6d235bd465309e12f4c56ea16e71111 Author: Daniel Vetter Date: Tue Feb 14 22:37:25 2012 +0100 drm/i915: reenable gmbus on gen3+ again and commit 0fb3f969c8683505fb7323c06bf8a999a5a45a15 Author: Daniel Vetter Date: Fri Mar 2 19:38:30 2012 +0100 drm/i915: enable gmbus on gen2 Unfortunately, GMBUS seems to fail on some CRT displays. Add a bit-banging fallback to CRT EDID reads. LKML-Reference: <201207251020.47637.maciej.rutecki@gmail.com> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=45881 Signed-off-by: Jani Nikula Tested-by: Alex Ferrando Cc: stable@vger.kernel.org (for 3.4+3.5) Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_crt.c | 36 +++++++++++++++++++++++++++++--- 1 file changed, 33 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c index 7ed4a41c3965..23bdc8cd1458 100644 --- a/drivers/gpu/drm/i915/intel_crt.c +++ b/drivers/gpu/drm/i915/intel_crt.c @@ -326,6 +326,36 @@ static bool intel_crt_detect_hotplug(struct drm_connector *connector) return ret; } +static struct edid *intel_crt_get_edid(struct drm_connector *connector, + struct i2c_adapter *i2c) +{ + struct edid *edid; + + edid = drm_get_edid(connector, i2c); + + if (!edid && !intel_gmbus_is_forced_bit(i2c)) { + DRM_DEBUG_KMS("CRT GMBUS EDID read failed, retry using GPIO bit-banging\n"); + intel_gmbus_force_bit(i2c, true); + edid = drm_get_edid(connector, i2c); + intel_gmbus_force_bit(i2c, false); + } + + return edid; +} + +/* local version of intel_ddc_get_modes() to use intel_crt_get_edid() */ +static int intel_crt_ddc_get_modes(struct drm_connector *connector, + struct i2c_adapter *adapter) +{ + struct edid *edid; + + edid = intel_crt_get_edid(connector, adapter); + if (!edid) + return 0; + + return intel_connector_update_modes(connector, edid); +} + static bool intel_crt_detect_ddc(struct drm_connector *connector) { struct intel_crt *crt = intel_attached_crt(connector); @@ -336,7 +366,7 @@ static bool intel_crt_detect_ddc(struct drm_connector *connector) BUG_ON(crt->base.type != INTEL_OUTPUT_ANALOG); i2c = intel_gmbus_get_adapter(dev_priv, dev_priv->crt_ddc_pin); - edid = drm_get_edid(connector, i2c); + edid = intel_crt_get_edid(connector, i2c); if (edid) { bool is_digital = edid->input & DRM_EDID_INPUT_DIGITAL; @@ -544,13 +574,13 @@ static int intel_crt_get_modes(struct drm_connector *connector) struct i2c_adapter *i2c; i2c = intel_gmbus_get_adapter(dev_priv, dev_priv->crt_ddc_pin); - ret = intel_ddc_get_modes(connector, i2c); + ret = intel_crt_ddc_get_modes(connector, i2c); if (ret || !IS_G4X(dev)) return ret; /* Try to probe digital port for output in DVI-I -> VGA mode. */ i2c = intel_gmbus_get_adapter(dev_priv, GMBUS_PORT_DPB); - return intel_ddc_get_modes(connector, i2c); + return intel_crt_ddc_get_modes(connector, i2c); } static int intel_crt_set_property(struct drm_connector *connector, -- GitLab