Bug 9278

Summary:	Unable to write the value "100" to brightness proc entry
Product:	ACPI	Reporter:	Danny Baumann (dannybaumann)
Component:	Power-Video	Assignee:	Zhang Rui (rui.zhang)
Status:	CLOSED PATCH_ALREADY_AVAILABLE
Severity:	normal	CC:	acpi-bugzilla
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.23	Subsystem:
Regression:	---	Bisected commit-id:
Attachments:	Adjust buffer size so that "100" can be written

Description Danny Baumann 2007-11-02 06:21:24 UTC

Most recent kernel where this bug did not occur: none
Distribution: Fedora 8
Problem Description:

Currently, one can't write the value "100" to /proc/acpi/video/.../LCD/brightness. This is rejected because the buffer is too small - while 4 bytes are written (100 + NULL byte), the space is only sufficient for 3 bytes.

Comment 1 Danny Baumann 2007-11-02 06:22:15 UTC

Created attachment 13374 [details]
Adjust buffer size so that "100" can be written

This patch increases the buffer size so that the value "100" can be written successfully.

Comment 2 Zhang Rui 2007-11-05 00:16:40 UTC

Oops, no one tried this before? :p
I'm sure you can use "/sys/class/backlight/.../" to set your brightness level correctly, right?

Comment 3 Zhang Rui 2007-11-05 00:17:41 UTC

Mark this bug as PATCH_ALREADY_AVAILABLE.

But as the proc I/F is deprecated by the new sys I/F, and there has been already an alternative for acpi video brightness control. Not sure this will be merged or not. :)

Comment 4 Danny Baumann 2007-11-05 00:36:43 UTC

(In reply to comment #3)
> Mark this bug as PATCH_ALREADY_AVAILABLE.
> 
> But as the proc I/F is deprecated by the new sys I/F, and there has been
> already an alternative for acpi video brightness control. Not sure this will
> be
> merged or not. :)

Well, when will the procfs support be dropped completely? If it's in 2.6.24, I'm completely fine with that. If later, I think it should be working correctly as long as it's included ;)
>

Comment 5 Len Brown 2007-11-18 22:55:59 UTC

c88c5786d3df51ccfa4e2d111fc9c8fc0f5b2797
(ACPI: Video: Increase buffer size for writes to brightness proc file.)
applied to acpi tree

Comment 6 Len Brown 2007-12-03 22:47:53 UTC

shipped in linux-2.6.24-rc4
closed