On Mon, 29 Mar 2010 11:47:27 +0200 Jiri Kosina [off-list ref] wrote:

On Sat, 27 Mar 2010, Bruno Prémont wrote:

quoted

+#ifdef CONFIG_PM
+static int picolcd_suspend(struct hid_device *hdev)
+{
+	dbg_hid(PICOLCD_NAME " device ready for suspend\n");
+	return 0;
+}
+
+static int picolcd_resume(struct hid_device *hdev)
+{
+	return 0;
+}
+
+static int picolcd_reset_resume(struct hid_device *hdev)
+{
+	int ret;
+	ret = picolcd_reset(hdev);
+	if (ret)
+		dbg_hid(PICOLCD_NAME " resetting our device failed: %d\n", ret);
+	return 0;
+}
+#endif

[ ... ]

quoted

+static struct hid_driver picolcd_driver = {
+	.name =          "hid-picolcd",
+	.id_table =      picolcd_devices,
+	.probe =         picolcd_probe,
+	.remove =        picolcd_remove,
+	.raw_event =     picolcd_raw_event,
+#ifdef CONFIG_PM
+	.suspend =       picolcd_suspend,
+	.resume =        picolcd_resume,
+	.reset_resume =  picolcd_reset_resume,
+#endif
+};

struct hid_driver doesn't provide power-management related callbacks.
So I guess that you have either not tested this feature at all, or
you have some extra patch somewhere which adds such callbacks to HID
core, but you haven't sent it out for review?

In any cases, this will very likely cause compilation failure with 
CONFIG_PM turned on.

That's the patch I referred to (under series introduction mail) when
saying:

The series depends on my previous patch adding HID suspend support
(I've not yet looked at improving it).

Link to the patch:
  http://lkml.org/lkml/2010/2/24/233

Especially the reset-resume part is important as the device has to be
reprogrammed with framebuffer content, brightness/contrast in that case.


As stated, Oliver didn't like the implementation of the addition of
those hooks too much and I have yet to look at improving it.

Thanks,
Bruno