Messages in this thread | | | Date | Sun, 5 Feb 2006 14:34:46 +0000 | From | Matthew Garrett <> | Subject | Re: [PATCH, RFC] Driver for reading HP laptop LCD brightness |
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On Sun, Feb 05, 2006 at 03:27:26PM +0100, Arjan van de Ven wrote:
> disable_irq() and enable_irq() are really really evil. Are you sure you > need these? To me on first sight it looks like a bug (think of shared > interrupts for example), can you explain what you are trying to achieve > with these?
We're talking to the hardware directly. There's a potential race where the BIOS will try to access the cmos at the same time, with potentially interesting results (We set the address we want to read with the outb. The BIOS runs, outbs its own address, and then reads. We then read from the address the BIOS was looking at, rather than what we were looking at).
On all the hardware this will run on, IRQ 8 is the RTC. I don't believe it can share interrupts. -- Matthew Garrett | mjg59@srcf.ucam.org - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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