Attachment 51643 Details for Bug 41059 – Patch to ignore non-existent i2c buses

[patch] Patch to ignore non-existent i2c buses

0001-Mark-non-existent-i2c-buses-as-disabled-and-skip-the.patch (text/plain), 3.81 KB, created by Eugeni Dodonov on 2011-09-26 16:45:04 UTC

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Creator: Eugeni Dodonov

Created: 2011-09-26 16:45:04 UTC

Size: 3.81 KB

patch

obsolete

>From fca0ec4edc16095e7f4cce240b563d9b9be9cd04 Mon Sep 17 00:00:00 2001
>From: Eugeni Dodonov <eugeni.dodonov@intel.com>
>Date: Thu, 22 Sep 2011 21:50:33 -0300
>Subject: [PATCH] Mark non-existent i2c buses as disabled and skip them in the
> future.
>
>This adds a check for the -ENODEV error when adding a i2c device, provided
>by the test_bus() routine. When it happens, we mark the i2c device as
>disabled, and skip it in the future.
>
>This should avoid excessively long delays when communicating with the
>hardware, such as in https://bugs.freedesktop.org/show_bug.cgi?id=41059
>for example.
>
>This version of the patch relies on the testing facility of the
>i2c_algo_bit module. In order to use it, you need to add the following
>line into /etc/modprobe.conf or into /etc/modprobe.d/i2c_algo_bit.conf
>file (creating it when necessary):
>
>options i2c_algo_bit bit_test=1
>
>Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
>---
> drivers/gpu/drm/i915/i915_drv.h  |    1 +
> drivers/gpu/drm/i915/intel_i2c.c |   28 +++++++++++++++++++++++++++-
> 2 files changed, 28 insertions(+), 1 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>index 7916bd9..760ceff 100644
>--- a/drivers/gpu/drm/i915/i915_drv.h
>+++ b/drivers/gpu/drm/i915/i915_drv.h
>@@ -284,6 +284,7 @@ typedef struct drm_i915_private {
> 	struct intel_gmbus {
> 		struct i2c_adapter adapter;
> 		struct i2c_adapter *force_bit;
>+		int disabled;
> 		u32 reg0;
> 	} *gmbus;
> 
>diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
>index d98cee6..6bcb48e 100644
>--- a/drivers/gpu/drm/i915/intel_i2c.c
>+++ b/drivers/gpu/drm/i915/intel_i2c.c
>@@ -160,10 +160,17 @@ intel_gpio_create(struct drm_i915_private *dev_priv, u32 pin)
> 		GPIOF,
> 	};
> 	struct intel_gpio *gpio;
>+	int err;
> 
> 	if (pin >= ARRAY_SIZE(map_pin_to_reg) || !map_pin_to_reg[pin])
> 		return NULL;
> 
>+	/* Was pin already disabled? */
>+	if (dev_priv->gmbus[pin].disabled == 1) {
>+		printk(KERN_INFO "i915: pin %d is disabled, skipping\n", pin);
>+		return NULL;
>+    }
>+
> 	gpio = kzalloc(sizeof(struct intel_gpio), GFP_KERNEL);
> 	if (gpio == NULL)
> 		return NULL;
>@@ -186,8 +193,18 @@ intel_gpio_create(struct drm_i915_private *dev_priv, u32 pin)
> 	gpio->algo.timeout = usecs_to_jiffies(2200);
> 	gpio->algo.data = gpio;
> 
>-	if (i2c_bit_add_bus(&gpio->adapter))
>+	if ((err = i2c_bit_add_bus(&gpio->adapter)) < 0) {
>+		/* i2c communication failed, if it failed with -ENODEV, we have
>+		 * failed the bit testing so let's mark bus as invalid and skip
>+		 * it in the future */
>+		if (err == -ENODEV) {
>+			printk(KERN_WARNING "i915: i2c check for %s failed, disabling pin\n",
>+					gpio->adapter.name);
>+			dev_priv->gmbus[pin].disabled = 1;
>+		}
> 		goto out_free;
>+	}
>+	gpio->dev_priv->gmbus[pin].disabled = 0;
> 
> 	return &gpio->adapter;
> 
>@@ -233,6 +250,13 @@ gmbus_xfer(struct i2c_adapter *adapter,
> 					       adapter);
> 	struct drm_i915_private *dev_priv = adapter->algo_data;
> 	int i, reg_offset;
>+	int pin = bus->reg0 & 0xff;
>+
>+	/* Was pin already disabled? */
>+	if (pin < GMBUS_NUM_PORTS && dev_priv->gmbus[pin].disabled == 1) {
>+		printk(KERN_INFO "i915: gmbus_xfer: pin %d is disabled, skipping\n", pin);
>+		return -ENODEV;
>+    }
> 
> 	if (bus->force_bit)
> 		return intel_i2c_quirk_xfer(dev_priv,
>@@ -328,6 +352,7 @@ timeout:
> 	I915_WRITE(GMBUS0 + reg_offset, 0);
> 
> 	/* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */
>+	printk(KERN_INFO "gmbus_xfer: timeout: fallback to gpio_create\n");
> 	bus->force_bit = intel_gpio_create(dev_priv, bus->reg0 & 0xff);
> 	if (!bus->force_bit)
> 		return -ENOMEM;
>@@ -401,6 +426,7 @@ int intel_setup_gmbus(struct drm_device *dev)
> 		bus->reg0 = i | GMBUS_RATE_100KHZ;
> 
> 		/* XXX force bit banging until GMBUS is fully debugged */
>+		printk(KERN_INFO "setup_gmbus: trying intel_gpio_create\n");
> 		bus->force_bit = intel_gpio_create(dev_priv, i);
> 	}
> 
>-- 
>1.7.6.4
>

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