Messages in this thread |  | | Date | Thu, 21 Sep 2000 06:01:08 -0700 | | From | quasi@quasisof ... | | Subject | Re: cpu reset on laptops and microcode update. |
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> > Tigran Aivazian <tigran@veritas.com> on 21/09/2000 09:50:53 > > > > Please respond to Tigran Aivazian <tigran@veritas.com> > > > > To: linux-kernel@vger.kernel.org > > cc: (bcc: Richard J Moore/UK/IBM) > > Subject: cpu reset on laptops and microcode update. > > > > Hi guys, > > > > A long time ago I noticed a curious feature on my Dell Latitude CPx > > H-450GT laptop - rebooting it via "shutdown -r now" (and therefore going > > through BIOS) does not discard the microcode applied to the CPU. But I > > would expect it to be discarded as prescribed by Intel manuals, on #RESET. > > > > Does it mean that rebooting a laptop does not actually ever reset the > > CPU? (this would imply that the BIOS is also a protected mode software?) > > > > Of course, doing "shutdown -h now" and switching off the power does > > discard the microcode as expected. > > > > Any thoughts? I post on linux-kernel because, potentially, your thoughts > > may become relevant to the content of arch/i386/kernel/microcode.c which > > is part of Linux kernel :) > > > > Regards, > > Tigran > > > I wouldn't have expected a reset to be done on shutdown -r since that > doesn't force POST to run. My guess is that we go directly to the BIOS to > read the bootstrap (INT 19 is it??) > > > Richard Moore - RAS Project Lead - Linux Technology Centre. > > http://oss.software.ibm.com/developerworks/opensource/linux > Office: (+44) (0)1962-817072, Mobile: (+44) (0)7768-298183 > PISC, MP135 Galileo Centre, Hursley Park, Winchester, SO21 2JN, UK
I was curious about this when with OS/2, the Win-OS2 media player would not stop when I gave it the three-finger-salute while it was still playing a CD-ROM, that is, until it began to re-boot. When it re-boots, the microcode should get replaced during the bootstrap process.
Douglas Ostling
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