Please answer the questions that I asked, not something else entirely. "Liu, Chuansheng" <chuansheng....@intel.com> wrote: >Hello hpa, > >> I could be wrong and the cold/warm reset values in CF9 end up having >> exactly the same function as the magic BIOS signature does; if so, >then >> I would like to be told so explicitly, ideally with an explanation >about >> how it works on the hw level (or a pointer to relevant documentation, >> Intel internal docs are fine.) >The Intel link is here for SandyBridge platform: >https://houston.fm.intel.com/wiki/doku.php?id=svwiki:projects:sandybridge:testplans:reset:start >And we have one internal baytrail platform doc refered it also. > >> >> Finally, again, does this solve a real problem? >Yes, we already have the 0xCF9 rebooting function, why not support the >COLD/WARM reset both? >Thanks. > > >For safety and compatibility, we prepared the below patch, do you think >is it making sense? > > > >From: liu chuansheng <chuansheng....@intel.com> >Subject: [PATCH] X86, reboot: supporting COLD reset thru 0xcf9 port > >Current X86 rebooting function supports the platform reset thru >port 0xcf9, but currently it hardcoded only for WARM reset that >writing 0x6 into port 0xcf9. > >Here we added the support the COLD reset that writing 0xe thru >port 0xcf9, and the actual reset type is determined by reboot_mode >variable. > >Also for safety and compatibility, we will set the default reboot >mode as WARM reset for several Apple MacBooks. > >Signed-off-by: Li Fei <fei...@intel.com> >Signed-off-by: liu chuansheng <chuansheng....@intel.com> >--- > arch/x86/kernel/reboot.c | 20 ++++++++++++++++++-- > 1 files changed, 18 insertions(+), 2 deletions(-) > >diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c >index 563ed91..b4a1cb4 100644 >--- a/arch/x86/kernel/reboot.c >+++ b/arch/x86/kernel/reboot.c >@@ -116,6 +116,12 @@ static int __init set_pci_reboot(const struct >dmi_system_id *d) > { > if (reboot_type != BOOT_CF9) { > reboot_type = BOOT_CF9; >+ >+ /* The default reboot_mode value is COLD reset(0) for >X86 platform, >+ * here for safety and compatibility, we set the >default reboot >+ * mode as WARM reset for several Apple MacBooks. >+ */ >+ reboot_mode = REBOOT_WARM; >pr_info("%s series board detected. Selecting %s-method for reboots.\n", > "PCI", d->ident); > } >@@ -511,10 +517,20 @@ static void >native_machine_emergency_restart(void) > > case BOOT_CF9_COND: > if (port_cf9_safe) { >- u8 cf9 = inb(0xcf9) & ~6; >+ u8 reboot_val; >+ u8 cf9; >+ >+ if (reboot_mode == REBOOT_WARM) >+ reboot_val = 0x6; >+ else >+ reboot_val = 0xe; >+ >+ cf9 = inb(0xcf9) & ~reboot_val; > outb(cf9|2, 0xcf9); /* Request hard reset */ > udelay(50); >- outb(cf9|6, 0xcf9); /* Actually do the >reset */ >+ >+ /* Actually do the reset */ >+ outb(cf9|reboot_val, 0xcf9); > udelay(50); > } > reboot_type = BOOT_KBD;
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