Re: [PATCH] acpi: Avoid dropping rapid hotkey events (or other GPEs) on Asus EeePC
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2008-08-13 10:47:29
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On Wed, 13 Aug 2008 11:21:10 +0100 Alan Jenkins [off-list ref] wrote:
Andrew Morton wrote:quoted
Did this get fixed yet? I have an patch in -mm which I just restored (I had to tempdrop it because the acpi tree was busted for some time). But it seems to be old. http://bugzilla.kernel.org/show_bug.cgi?id=10919 is marked "resolved" but the reporter (Maximilian) seems to think otherwise. 2.6.26.x is, afaik, still unfixed, as is 2.6.27-rc.That's correct. I think this specific patch should go in 2.6.27 and 2.6.26-stable. No objections have been raised so far. I still need this patch to make my brightness and volume control keys usable in 2.6.27-rc3. (They auto-repeat fast enough to trigger the bug). This is true even after applying the latest patches from bug 10919 (#25 + #27).
Confusing. Please send the patch which you think we should apply.
I think the 10919 fix makes it harder to reproduce, but it definitely still happens. I guess this is because the polling-driven EC transactions add 1ms delays between each byte. The slower timings leave a window where the buggy behaviour of my EC can make a difference. (It has been seen to clear the "pending event" bit after a single event is read, despite having more events pending). There are more serious consequences of this bug. After a while it can confuse the EC enough to cause lockups or reboots during boot, or after pressing a single hotkey. This bad state is preserved over reboots, even into known good kernels. Fortunately the badness clears when power is removed for a long enough period. For a while I was worried that something had physically burnt out.
Oh gad. And there's no workaround?