Commit c6744955 authored Aug 06, 2008 by Samuel Sieb Committed by Ingo Molnar Aug 20, 2008

x86: fix "kernel won't boot on a Cyrix MediaGXm (Geode)"



Cyrix MediaGXm/Cx5530 Unicorn Revision 1.19.3B has stopped
booting starting at v2.6.22.

The reason is this commit:

> commit f25f64ed
> Author: Juergen Beisert <juergen@kreuzholzen.de>
> Date:   Sun Jul 22 11:12:38 2007 +0200
>
>     x86: Replace NSC/Cyrix specific chipset access macros by inlined functions.

this commit activated a macro which was dormant before due to (buggy)
macro side-effects.

I've looked through various datasheets and found that the GXm and GXLV
Geode processors don't have an incrementor.

Remove the incrementor setup entirely.  As the incrementor value
differs according to clock speed and we would hope that the BIOS
configures it correctly, it is probably the right solution.

Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 8a7c5ef3

arch/x86/kernel/cpu/cyrix.c

+0 −18

Original line number	Diff line number	Diff line
		@@ -134,23 +134,6 @@ static void __cpuinit set_cx86_memwb(void)
		setCx86(CX86_CCR2, getCx86(CX86_CCR2) \| 0x14);
		}

		static void __cpuinit set_cx86_inc(void)
		{
		unsigned char ccr3;

		printk(KERN_INFO "Enable Incrementor on Cyrix/NSC processor.\n");

		ccr3 = getCx86(CX86_CCR3);
		setCx86(CX86_CCR3, (ccr3 & 0x0f) \| 0x10); /* enable MAPEN */
		/* PCR1 -- Performance Control */
		/* Incrementor on, whatever that is */
		setCx86(CX86_PCR1, getCx86(CX86_PCR1) \| 0x02);
		/* PCR0 -- Performance Control */
		/* Incrementor Margin 10 */
		setCx86(CX86_PCR0, getCx86(CX86_PCR0) \| 0x04);
		setCx86(CX86_CCR3, ccr3); /* disable MAPEN */
		}

		/*
		* Configure later MediaGX and/or Geode processor.
		*/
		@@ -174,7 +157,6 @@ static void __cpuinit geode_configure(void)

		set_cx86_memwb();
		set_cx86_reorder();
		set_cx86_inc();

		local_irq_restore(flags);
		}

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