On 06/16/2017 08:13 PM, Eric Anholt wrote:
Archit Taneja <architt@xxxxxxxxxxxxxx> writes:
On 06/16/2017 02:11 AM, Eric Anholt wrote:
If the panel-bridge is being set up after the drm_mode_config_reset(),
then the connector's state would never get initialized, and we'd
dereference the NULL in the hotplug path. We also need to register
the connector, so that userspace can get at it.
Shouldn't the KMS driver make sure the panel-bridge is set up before
drm_mode_config_reset? Is it the case when we're inserting the
panel-bridge driver as a module?
All the connectors that have been added are registered automatically
when drm_dev_register() is called by the KMS driver. Registering a
connector in the middle of setting up our driver is prone to race
conditions if the userspace decides to use them immediately.
Yeah, this is fixing initializing panel_bridge at DSI host_attach time,
which in the case of a panel module that creates the DSI device
(adv7533-style, like you said I should use as a reference) will be after
drm_mode_config_reset() and drm_dev_register().
Okay. In the case of the msm kms driver, we defer probe until the
adv7533 module is inserted, only then we proceed to drm_mode_config_reset()
and drm_dev_register(). I assumed this was the general practice followed by
most kms drivers. I.,e the kms driver defers probe until all connector
related modules are inserted, and only then proceed to create a drm device.
Feedback from others on this would be appreciated, though.
Thanks,
Archit
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