Jean,

On Fri, 2010-11-05 at 13:51 -0400, Jean Delvare wrote:

On Fri, 5 Nov 2010 09:58:01 -0700, Guenter Roeck wrote:

...

On Fri, 2010-11-05 at 12:21 -0400, Randy Dunlap wrote:

...

/sys/bus/i2c/devices/i2c-0/name:gmbus disabled /sys/bus/i2c/devices/i2c-10/name:GPIOE /sys/bus/i2c/devices/i2c-11/name:gmbus reserveddpd /sys/bus/i2c/devices/i2c-12/name:GPIOF /sys/bus/i2c/devices/i2c-13/name:gmbus (null) /sys/bus/i2c/devices/i2c-14/name:GPIO?

The above two lines look a bit fishy to me.

I had the exact same thought. And "reserveddpd" looks odd as well.

...

Wonder if 7b5337ddbaf7e4b71ef6fd6307c6f9ef84f636e9 or one of the other recent changes in drivers/gpu/drm/i915/intel_i2c.c caused some havoc.

Thanks for the pointer. But if Randy is running 2.6.37-rc1, he doesn't have this commit yet. Upgrading to 2.6.37-rc1-git3 might be a good idea. Especially as rc1 also lacks cb8ea7527b813dd6e19fb07328f7867a5f0a8d0a, if I understand what git name-rev is telling me. Apparently the "GMBUS" code was reverted (whatever it is) because it caused trouble. Maybe this is the trouble Randy just met.

Looking at the code, I indeed see a couple things which need fixing. Randy, please test this patch (on top of rc1-git3) Hopefully it will fix your adapter names, and possibly solve your crash (but if you couldn't reproduce it, you won't be able to confirm this.)

From: Jean Delvare khali@linux-fr.org Subject: drm/i915: Fix I2C adapter registration

Fix many small bugs in I2C adapter registration:

• Properly reject unsupported GPIO pin.
• Fix improper use of I2C_NAME_SIZE (which is the size of i2c_client.name, not i2c_adapter.name.)
• Prefix adapter names with "i915" so that the user knows what the I2C channel is connected to.
• Fix swapped characters in the string used to name the GPIO-based adapter.
• Add missing comma in gmbus name table.

Signed-off-by: Jean Delvare khali@linux-fr.org

I think it would make sense to push this patch into the kernel, even if it does not fix the problem reported by Randy. The problems are obvious enough.

Copying subsystem maintainers and mailing lists for input.

Thanks, Guenter

drivers/gpu/drm/i915/intel_i2c.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)

--- linux-2.6.37-rc1.orig/drivers/gpu/drm/i915/intel_i2c.c 2010-11-02 09:19:35.000000000 +0100 +++ linux-2.6.37-rc1/drivers/gpu/drm/i915/intel_i2c.c 2010-11-05 18:38:15.000000000 +0100 @@ -160,7 +160,7 @@ intel_gpio_create(struct drm_i915_privat }; struct intel_gpio *gpio;

• if (pin < 1 || pin > 7)

• if (pin >= ARRAY_SIZE(map_pin_to_reg) || !map_pin_to_reg[pin]) return NULL;

  gpio = kzalloc(sizeof(struct intel_gpio), GFP_KERNEL);

@@ -172,7 +172,8 @@ intel_gpio_create(struct drm_i915_privat gpio->reg += PCH_GPIOA - GPIOA; gpio->dev_priv = dev_priv;

• snprintf(gpio->adapter.name, I2C_NAME_SIZE, "GPIO%c", "?BACDEF?"[pin]);

• snprintf(gpio->adapter.name, sizeof(gpio->adapter.name), "i915 GPIO%c",

•  "?BACDE?F"[pin]);
  

  gpio->adapter.owner = THIS_MODULE; gpio->adapter.algo_data = &gpio->algo; gpio->adapter.dev.parent = &dev_priv->dev->pdev->dev;

@@ -349,7 +350,7 @@ int intel_setup_gmbus(struct drm_device "panel", "dpc", "dpb",

• "reserved"
  

• "reserved",
  

  "dpd", }; struct drm_i915_private *dev_priv = dev->dev_private;

@@ -366,8 +367,8 @@ int intel_setup_gmbus(struct drm_device bus->adapter.owner = THIS_MODULE; bus->adapter.class = I2C_CLASS_DDC; snprintf(bus->adapter.name,

• 	 I2C_NAME_SIZE,
  

• 	 "gmbus %s",
  

• 	 sizeof(bus->adapter.name),
  

• 	 "i915 gmbus %s",
   names[i]);
  
  

  bus->adapter.dev.parent = &dev->pdev->dev;