[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1 of 5] rombios/keyboard: Don't needlessly poll the status register
On 26/11/12 16:48, Ian Campbell wrote: > On Mon, 2012-11-26 at 16:41 +0000, Andrew Cooper wrote: >> Repeated polling of the status register is not going to change its value, > but the passage of time while doing multiple polls might? If this is not > the case then something needs to be said about why not. In reality, we failed to ever get a keypress on the console to appear here, even when trying. If I remember correctly (it was a long time ago now), this code runs before the PCI bus is scanned, so is really early on during boot. > >> so >> don't needlessly take 8192 traps to Qemu when 1 will do. >> >> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> >> >> diff -r 0049de3827bc -r 1728fb789940 tools/firmware/rombios/rombios.c >> --- a/tools/firmware/rombios/rombios.c >> +++ b/tools/firmware/rombios/rombios.c >> @@ -1805,12 +1805,12 @@ keyboard_init() >> while ( (inb(0x64) & 0x02) && (--max>0)) outb(0x80, 0x00); >> >> /* flush incoming keys */ >> - max=0x2000; >> + max=2; >> while (--max > 0) { >> outb(0x80, 0x00); >> if (inb(0x64) & 0x01) { >> inb(0x60); >> - max = 0x2000; >> + max = 2; >> } >> } >> >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@xxxxxxxxxxxxx >> http://lists.xen.org/xen-devel > -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 900, http://www.citrix.com _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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