Re: [PATCH] ACPI / PM: Traverse video_device_list for backlightrestoration

[Matthias Hopf]

A bit of background about this patch:


acpi_video_bus_get_devices() explicitly calls acpi_video_device_enumerate()
before acpi_video_bus_get_one_device(), which does acpi_video_device_bind().

In _enumerate(), active_list[] is created, with .bind_info explicitly set to
NULL, while the related .bind_info entry in video_device_list is set to the
acpi_video_device ptr in _bind().

The .bind_info is later used in acpi_video_resume() to re-set the backlight
- but it's only evaluated on the active_list[], on which all .bind_info are
NULL by construction.  This results in backlight not being restored, if the
BIOS doesn't do this by itself already.


The patch resolves this by replacing the active_list[] traversal by a
video_device_list traversal, but due to the nature of the issue I'm unsure
whether the original issue isn't of more principal quality.  I don't understand
why the list is (partially) transformed into an array in the first place,
especially as both the array *and* the list are used in the code...


Thanks

Matthias

-- 
Matthias Hopf <mhopf@xxxxxxx>      __        __   __
Maxfeldstr. 5 / 90409 Nuernberg   (_   | |  (_   |__          mat@xxxxxxxxx
Phone +49-911-74053-715           __)  |_|  __)  |__  R & D   www.mshopf.de
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/