On Tue, 25 Jan 2005 20:25:20 +0100, Vojtech Pavlik <[EMAIL PROTECTED]> wrote: > On Tue, Jan 25, 2005 at 02:17:33PM -0500, Dmitry Torokhov wrote: > > On Tue, 25 Jan 2005 11:51:39 +0100, Andries Brouwer <[EMAIL PROTECTED]> > > wrote: > > > On Tue, Jan 25, 2005 at 02:41:14AM -0500, Dmitry Torokhov wrote: > > > > > > > Recently there was a patch from Alan regarding access timing violations > > > > in i8042. It made me curious as we only wait between accesses to status > > > > register but not data register. I peeked into FreeBSD code and they use > > > > delays to access both registers and I wonder if that's the piece that > > > > makes i8042 mysteriously fail on some boards. > > > > > > You are following this much more closely than I do, but isn't the > > > usual complaint "2.4 works, 2.6 fails"? > > > > > > > Quite often it is but too much has changed in input layer to pinpoing > > exact cause of the failure and I am open to any suggestions. Common > > problems I see: > > > > 1. ACPI sometimes interferes with i8042, especially battery status > > polling. I am concerned about embedded controller access as well, it > > looks like it takes sweet time to read/write data to it and ec.c does > > it with interrupts disabled. > > Furthermore, the EC and the i8042 are often the same chip, resulting in > the i8042 not answering when EC is busy. Enabling interrupts won't help.
It might or it might not, I think it really depends on firmware implementation. > > Also, In 2.4 if BIOS detected PS/2 mouse we trusted it and did not do > > any additional checks, now that i8042 is not x86 specific we do > > everything by hand and it looks like some hardware is not expecting > > it... > > We may be able to loosen the checks again now that 98% of machines do > have the PS/2 mouse port if they have the AT keyboard port. > Maybe only for specific machines - the report was about a Toshiba and it looks like they have quite a few problems with their KBCs - bouncing keys, not being able to sustain full Synaptics 480 bytes/s rate... -- Dmitry - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/