Re: [PATCH v2 2/2] drm/bridge: Add PTN3460 bridge driver

[Thierry Reding <thierry.reding@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 999 bytes --]

On Wed, Aug 14, 2013 at 04:47:38PM -0400, Sean Paul wrote:
[...]
> +int ptn3460_init(struct drm_device *dev, struct drm_encoder *encoder,
> +		struct i2c_client *client, struct device_node *node)
[...]
> +	ptn_bridge->gpio_pd_n = of_get_named_gpio(node, "powerdown-gpio", 0);

of_get_named_gpio() can return -EPROBE_DEFER and I wonder how you handle
that in the driver that uses ptn3460_init(). Since you pass in an
initialized drm_device, you'd need to undo all of that in case of
-EPROBE_DEFER. Well I guess you'd have to do that in case of any error,
but it makes things difficult to handle for drivers.

For instance on Tegra we pretty much delay DRM initialization until all
required subdevices (there are quite a few) have been probed, so if we
wanted to use this function we'd have to call it after all drivers have
been probed because only then do we have access to a struct drm_device.
That will cause other problems, however, because at that point we can't
defer probing anymore.

Thierry

[-- Attachment #2: Type: application/pgp-signature, Size: 836 bytes --]