On Fri, Oct 07, 2011 at 07:00:42PM -0300, Eugeni Dodonov wrote:
This adds a new function intel_drm_get_valid_edid, which is used instead of drm_get_edid within the i915 driver.
It does a similar check to the one in previous patch, but it is limited to i915 driver.
The check is similar to the first part of EDID discovery performed by the drm_do_probe_ddc_edid. In case the i2c_transfer fails with the -ENXIO result, we know that the i2c_algo_bit was unable to locate the hardware, so we give up on further edid discovery.
They should also fix https://bugs.freedesktop.org/show_bug.cgi?id=41059
v2: change printk level to KERN_DEBUG to avoid filling up dmesg
Signed-off-by: Eugeni Dodonov eugeni.dodonov@intel.com
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index d98cee6..77115b9 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -470,3 +470,36 @@ void intel_teardown_gmbus(struct drm_device *dev) kfree(dev_priv->gmbus); dev_priv->gmbus = NULL; }
+/**
- intel_drm_get_valid_edid - gets edid from existent adapters only
- @connector: DRM connector device to use
- @adapter: i2c adapter
- Verifies if the i2c adapter is responding to our queries before
- attempting to do proper communication with it. If it does,
- retreive the EDID with help of drm_get_edid
- */
+struct edid * +intel_drm_get_valid_edid(struct drm_connector *connector,
struct i2c_adapter *adapter)+{
- unsigned char out;
- int ret;
- struct i2c_msg msgs[] = {
{.addr = 0x50,.flags = 0,.len = 1,.buf = &out,}- };
- /* Let's try one edid transfer */
- ret = i2c_transfer(adapter, msgs, 1);
- if (ret == -ENXIO) {
printk(KERN_DEBUG "i915: adapter %s not responding: %d\n",adapter->name, ret);return NULL;- }
- return drm_get_edid(connector, adapter);
+}
I think you may as well optimistically try to get the edid_data here. The problem is, in the success case you add ~10 i2c clocks because you next call drm_get_edid. If you optimistacally try to do both you should receive the -ENXIO after the slaves ignore the address byte, and not lose time. (So win on exists case, lose a *slight* amount of CPU time in fail case).
Now if you do that I think most of the code can be taken from intel_ddc_probe. Just modify that function to take the args you need (dev_priv, and adatper I am thinking). I only see one caller of that function, which can easily be modified.
Ben