Messages in this thread | | | Date | Thu, 21 Jan 2010 15:39:25 -0600 | Subject | Re: [PATCH] Disable i8042 checks on Intel Apple Macs | From | Robert Hancock <> |
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On Thu, Jan 21, 2010 at 12:55 PM, Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > On Wed, Jan 20, 2010 at 06:41:56PM -0600, Robert Hancock wrote: >> On 01/20/2010 12:23 PM, Bastien Nocera wrote: >> >As those computers never had any i8042 controllers, and the >> >current lookup code could potentially lock up/hang/wait for >> >timeout for long periods of time. >> > >> >Fixes intermittent hangs on boot on a MacbookAir1,1 >> > >> >Signed-off-by: Bastien Nocera<hadess@hadess.net> >> >> I assume this is happening because of this code in >> drivers/input/serio/i8042-x86ia64io.h: >> >> if (!i8042_pnp_kbd_devices && !i8042_pnp_aux_devices) { >> i8042_pnp_exit(); >> #if defined(__ia64__) >> return -ENODEV; >> #else >> printk(KERN_INFO "PNP: No PS/2 controller found. >> Probing ports directly.\n"); >> return 0; >> #endif >> >> In other words, on x86, if PNP and/or ACPI don't indicate any PS/2 >> controller exists, we randomly bang on the ports in the expectation >> they'll be there anyway. This seems rather misguided. > > Basically, we do not trust BIOS writers on x86 ;) In the past there were > occasions when they forgot to mention presence of KBD/AUX in DSDT and > elsewhere which lead to non-functional keyboard/mouse.
Are we certain about that? Any pointers to reports?
> >> It would seem >> like a better idea to fix this rather than adding yet another DMI >> list (especially since there likely are, or will be, machines >> without i8042 other than Macs). >> > > If they are not Macs that mean they are tested with windows and thus > expect probes in i8042 port region so no harm done. In a few years if > everyone uses USB only we could add a year threshold to trust ACPI/PNP > data.
Macs will be tested with Windows too, so obviously it manages to avoid this problem somehow, and I very much doubt it has an Apple-specific check.. -- 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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