Messages in this thread | | | Date | Tue, 3 Aug 2010 12:11:57 +0200 | From | Matthias Hopf <> | Subject | Re: [PATCH] ACPI / PM: Traverse video_device_list for backlight restoration |
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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@suse.de> __ __ __ Maxfeldstr. 5 / 90409 Nuernberg (_ | | (_ |__ mat@mshopf.de Phone +49-911-74053-715 __) |_| __) |__ R & D www.mshopf.de
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