Attachment 113348 Details for Bug 55228 – [PATCH] hack: try to set i2c bus speed to 100kbps via dpcd

[patch] [PATCH] hack: try to set i2c bus speed to 100kbps via dpcd

0001-hack-try-to-set-i2c-bus-speed-to-100kbps-via-dpcd.patch (text/plain), 1.52 KB, created by Ville Syrjala on 2015-02-11 12:16:48 UTC

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Creator: Ville Syrjala

Created: 2015-02-11 12:16:48 UTC

Size: 1.52 KB

patch

obsolete

>From 30990100e7ddb6b2bb3b599e5ed14329f7fbd0ff Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
>Date: Mon, 2 Feb 2015 14:09:04 +0200
>Subject: [PATCH] hack: try to set i2c bus speed to 100kbps via dpcd
>
>---
> drivers/gpu/drm/i915/intel_dp.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>index 5cecc20..8ba8dd3 100644
>--- a/drivers/gpu/drm/i915/intel_dp.c
>+++ b/drivers/gpu/drm/i915/intel_dp.c
>@@ -3579,6 +3579,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> 	struct drm_device *dev = dig_port->base.base.dev;
> 	struct drm_i915_private *dev_priv = dev->dev_private;
>+	u8 i2c_ctrl;
> 
> 	if (intel_dp_dpcd_read_wake(&intel_dp->aux, 0x000, intel_dp->dpcd,
> 				    sizeof(intel_dp->dpcd)) < 0)
>@@ -3586,6 +3587,18 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> 
> 	DRM_DEBUG_KMS("DPCD: %*ph\n", (int) sizeof(intel_dp->dpcd), intel_dp->dpcd);
> 
>+	i2c_ctrl = 0;
>+	intel_dp_dpcd_read_wake(&intel_dp->aux, 0x109, &i2c_ctrl, 1);
>+	DRM_DEBUG_KMS("Old i2c speed control: 0x%x\n", i2c_ctrl);
>+
>+	DRM_DEBUG_KMS("Trying to force i2c speed to 100kHz\n");
>+	i2c_ctrl = 0x8;
>+	drm_dp_dpcd_write(&intel_dp->aux, 0x109, &i2c_ctrl, 1);
>+
>+	i2c_ctrl = 0;
>+	intel_dp_dpcd_read_wake(&intel_dp->aux, 0x109, &i2c_ctrl, 1);
>+	DRM_DEBUG_KMS("New i2c speed control: 0x%x\n", i2c_ctrl);
>+
> 	if (intel_dp->dpcd[DP_DPCD_REV] == 0)
> 		return false; /* DPCD not present */
> 
>-- 
>2.0.5
>

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Attachments on bug 55228: 67564 | 67565 | 67566 | 67651 | 67677 | 71405 | 76194 | 91575 | 98101 | 113328 | 113346 | 113348 | 113421

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