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Re: can't boot 2.6.17-rc1



Benjamin Herrenschmidt writes:

> From my quick tests here (I'm travelling, so no much time), it looks
> like it's dying on the first msleep() (either radeonfb or whatever else
> if you play with driver order), which makes me strongly suspect the idle
> loop changes. I'll try to fix that when I'm back next week unless paulus
> beats me to it.

This patch fixes it for me on my powerbook (1.5GHz albook).  The issue
seems to be that the cpu objects to HID0_NAP being cleared in HID0.
If I have this code power_save_6xx_restore, it hangs:

_GLOBAL(power_save_6xx_restore)
	mfspr	r11,SPRN_HID0
	rlwinm	r11,r11,0,10,8		/* Clear NAP */
	mtspr	SPRN_HID0,r11
	b	transfer_to_handler_cont

If I take out that rlwinm, it boots.  Bizaare.

Paul.

diff --git a/arch/powerpc/kernel/idle_6xx.S b/arch/powerpc/kernel/idle_6xx.S
index 12a4efb..99e0356 100644
--- a/arch/powerpc/kernel/idle_6xx.S
+++ b/arch/powerpc/kernel/idle_6xx.S
@@ -157,35 +157,32 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
 /*
  * Return from NAP/DOZE mode, restore some CPU specific registers,
  * we are called with DR/IR still off and r2 containing physical
- * address of current.
+ * address of current.  R11 and CR contain HID0.  We have to preserve
+ * r10 and r12.
  */
 _GLOBAL(power_save_6xx_restore)
-	mfspr	r11,SPRN_HID0
-	rlwinm.	r11,r11,0,10,8	/* Clear NAP & copy NAP bit !state to cr1 EQ */
-	cror	4*cr1+eq,4*cr0+eq,4*cr0+eq
-BEGIN_FTR_SECTION
-	rlwinm	r11,r11,0,9,7	/* Clear DOZE */
-END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE)
-	mtspr	SPRN_HID0, r11
-
 #ifdef DEBUG
-	beq	cr1,1f
+	bf	9,1f
 	lis	r11,(nap_return_count-KERNELBASE)@ha
 	lwz	r9,nap_return_count@l(r11)
 	addi	r9,r9,1
 	stw	r9,nap_return_count@l(r11)
 1:
 #endif
-	
+
+#ifdef CONFIG_SMP
 	rlwinm	r9,r1,0,0,18
 	tophys(r9,r9)
 	lwz	r11,TI_CPU(r9)
 	slwi	r11,r11,2
+#else
+	li	r11,0
+#endif
 	/* Todo make sure all these are in the same page
-	 * and load r22 (@ha part + CPU offset) only once
+	 * and load r11 (@ha part + CPU offset) only once
 	 */
 BEGIN_FTR_SECTION
-	beq	cr1,1f
+	bf	9,1f
 	addis	r9,r11,(nap_save_msscr0-KERNELBASE)@ha
 	lwz	r9,nap_save_msscr0@l(r9)
 	mtspr	SPRN_MSSCR0, r9



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