On Fri, Feb 28, 2014 at 12:11:57PM +0800, Li, Aubrey wrote: > This patch is to introduce BOOT_EFI and BOOT_CF9 in the reboot sequence > loop, to fix the reboot problem on the known Intel Bay Trail-T based > platform, for example, ASUS-T100 and Dell Venue 8/11 Pro. These > platforms don't support ACPI reboot, we expect to call EFI runtime > service to handle this case, and CF9 is an alternate after EFI.
EFI reboot is still somewhat unreliable - it may be safe after the recent patches to provide a 1:1 mapping. CF9 is, as far as I know, not part of any spec, so it seems like a bad idea to put it in the default list. What do the ACPI reboot vectors look like on these systems? > - * 3) If still alive, write to the ACPI reboot register again > - * 4) If still alive, write to the keyboard controller again > + * 3) If still alive, call EFI runtime service > + * 4) If still alive, write to the PCI IO port 0xCF9 This is definitely incorrect. The ACPI write *must* occur twice in order to be effective on various systems. EFI shouldn't be attempted until after the second ACPI write. -- Matthew Garrett | mj...@srcf.ucam.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
