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Date: Tue, 8 May 2007 13:00:04 -0700 From: Andrew Morton <akpm@...ux-foundation.org> To: Alexander van Heukelum <heukelum@...lshack.com> Cc: "Antonino A. Daplas" <adaplas@...il.com>, Andi Kleen <ak@...e.de>, "H. Peter Anvin" <hpa@...or.com>, lkml <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] Make bootsector stub 16-bit-only (i386) On Tue, 8 May 2007 20:32:32 +0200 Alexander van Heukelum <heukelum@...lshack.com> wrote: > On Tue, May 08, 2007 at 03:28:17AM -0700, Andrew Morton wrote: > > On Sat, 5 May 2007 12:44:52 +0200 Alexander van Heukelum <heukelum@...lshack.com> wrote: > > > --- a/arch/i386/boot/bootsect.S > > > +++ b/arch/i386/boot/bootsect.S > > > @@ -44,7 +44,7 @@ #endif > > > _start: > > > > > > # Normalize the start address > > > - jmpl $BOOTSEG, $start2 > > > + jmpw $BOOTSEG, $start2 > > > > Sigh, another blow struck in the ongoing struggle between my Vaio and the > > rest of the world. > > > > Stone-cold black-screen lockup immediately upon boot. > > > > Stock FC5 install, config at > > http://userweb.kernel.org/~akpm/config-sony.txt > > Sigh... sounds impossible. > > I assume this is repeatable? 100% > And this patch changes behaviour? Yup. > What do you mean by immediate? Basically the last thing I see is grub. > Before or after decompression? Not sure - things happen pretty quickly and I suspect info is getting lost when the display is changing modes. > Fishy... As Andi and Peter have mentioned, this code is not executed. > There is only one user of the same memory area this early... video.S > uses it to store some collected data, but as far as I can see only the > 'CONFIG_VIDEO_RETAIN' code also reads it back. If it happens before > decompression, could you see if changing > #define CONFIG_VIDEO_RETAIN -> #undef CONFIG_VIDEO_RETAIN > in arch/i386/boot/video.S changes anything? > > Do you select a non-standard textmode? yep. > Does vga=ask show up? no. > *looks around some* > > Oh! A padding hole in a struct! That could be a problem. If the freeze > is after decompression, could you test if this makes it work again? I shall try that later in the day. > > --- > > Commit 89ec4c238e7a3d7e660291f3f1a8181381baad77 introduced a discrepancy > between the struct screen_info which is used by the C code, and the > PARAM_* offsets which are used in the real-mode kernel. This is an > attempt to rectify the situation, but I have no way to test it. > > Signed-off-by: Alexander van Heukelum <heukelum@...lshack.com> > > --- > > diff --git a/arch/i386/boot/bootsect.S b/arch/i386/boot/bootsect.S > diff --git a/arch/i386/boot/video.S b/arch/i386/boot/video.S > index 8143c95..8e404cb 100644 > --- a/arch/i386/boot/video.S > +++ b/arch/i386/boot/video.S > @@ -95,7 +95,8 @@ #define PARAM_VESAPM_SEG 0x2e > #define PARAM_VESAPM_OFF 0x30 > #define PARAM_LFB_PAGES 0x32 > #define PARAM_VESA_ATTRIB 0x34 > -#define PARAM_CAPABILITIES 0x36 > +#define PARAM_VESA_PAD 0x36 > +#define PARAM_CAPABILITIES 0x38 > > /* Define DO_STORE according to CONFIG_VIDEO_RETAIN */ > #ifdef CONFIG_VIDEO_RETAIN > diff --git a/include/linux/screen_info.h b/include/linux/screen_info.h > index b02308e..0a2e892 100644 > --- a/include/linux/screen_info.h > +++ b/include/linux/screen_info.h > @@ -41,8 +41,8 @@ struct screen_info { > u16 vesapm_off; /* 0x30 */ > u16 pages; /* 0x32 */ > u16 vesa_attributes; /* 0x34 */ > - u32 capabilities; /* 0x36 */ > - /* 0x3a -- 0x3b reserved for future expansion */ > + u16 vesa_pad; /* 0x36 */ > + u32 capabilities; /* 0x38 */ > /* 0x3c -- 0x3f micro stack for relocatable kernels */ > }; > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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