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[2.6 patch] ath9k: work around gcc ICEs

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[view original message]
From: Stephen Rothwell <sfr@...>
To: John W. Linville <linville@...>
Cc: <linux-next@...>, David Miller <davem@...>, LKML <linux-kernel@...>, Luis R. Rodriguez <lrodriguez@...>
Subject: linux-next: wireless-current tree build failure
Date: Tuesday, August 5, 2008 - 2:21 am

Hi John,


Today's linux-next build (powerpc allyesconfig) failed like this:


drivers/net/wireless/ath9k/hw.c: In function 'ath9k_hw_9280_spur_mitigate':

drivers/net/wireless/ath9k/hw.c:4660: internal compiler error: in expand_ex=

pr_real_1, at expr.c:9199


Clearly not our fault! :-) I have informed our toolchain person.  This

was using the Debian gcc-4.3.  It also fails using the Debian 4.2

compiler but not the 4.1 one.


For now, I will apply the following patch to just stop it building on

PowerPC.


--=20

Cheers,

Stephen Rothwell                    sfr@canb.auug.org.au

http://www.canb.auug.org.au/~sfr/
[view original message]
From: Adrian Bunk <bunk@...>
To: Stephen Rothwell <sfr@...>
Cc: John W. Linville <linville@...>, <linux-next@...>, David Miller <davem@...>, LKML <linux-kernel@...>, Luis R. Rodriguez <lrodriguez@...>
Subject: Re: linux-next: wireless-current tree build failure
Date: Tuesday, August 5, 2008 - 11:37 am

Alexandros Couloumbis already opened a bug for this issue on mips, which

also seems to be affected:

  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37014


It is a gcc bug, but we'll have to work around it in the ath9k driver.


cu

Adrian


-- 


       "Is there not promise of rain?" Ling Tan asked suddenly out

        of the darkness. There had been need of rain for many days.

       "Only a promise," Lao Er said.

                                       Pearl S. Buck - Dragon Seed


--
[view original message]
From: John W. Linville <linville@...>
To: Adrian Bunk <bunk@...>
Cc: Stephen Rothwell <sfr@...>, <linux-next@...>, David Miller <davem@...>, LKML <linux-kernel@...>, Luis R. Rodriguez <lrodriguez@...>
Subject: Re: linux-next: wireless-current tree build failure
Date: Tuesday, August 5, 2008 - 12:00 pm

I imagine that we would be happy to do that.  Anyone have a clue as to how?


John

--

John W. Linville

linville@tuxdriver.com

--
[view original message]
From: Adrian Bunk <bunk@...>
To: John W. Linville <linville@...>
Cc: Stephen Rothwell <sfr@...>, <linux-next@...>, David Miller <davem@...>, LKML <linux-kernel@...>, Luis R. Rodriguez <lrodriguez@...>
Subject: [2.6 patch] ath9k: work around gcc ICEs
Date: Tuesday, August 5, 2008 - 3:06 pm

Patch below, verified to fix the issue with the following compilers:

- powerpc 4.2.4

- powerpc latest 4.3 SVN

- powerpc latest 4.4 SVN

- mips 4.2.4

- mips 4.3.1


The patch has to be applied twice for fixing both copies of the


cu

Adrian


<--  snip  -->


This patch works around an internal compiler error (gcc bug #37014) in

all gcc 4.2 compilers and the gcc 4.3 series up to at least 4.3.1

on at least powerpc and mips.


Many thanks to Andrew Pinski for analyzing the gcc bug.


Signed-off-by: Adrian Bunk <bunk@kernel.org>


---

d1ec5b9fba6c50c7e98a85776a3b95d3a3a3179b

diff --git a/drivers/net/wireless/ath9k/hw.c b/drivers/net/wireless/ath9k/hw.c

index 1f6f393..5edc56d 100644

--- a/drivers/net/wireless/ath9k/hw.c

+++ b/drivers/net/wireless/ath9k/hw.c

@@ -4801,7 +4801,11 @@


 	for (i = 0; i < 123; i++) {

 		if ((cur_vit_mask > lower) && (cur_vit_mask < upper)) {

-			if ((abs(cur_vit_mask - bin)) < 75)

+

+			/* workaround for gcc bug #37014 */

+			volatile int tmp = abs(cur_vit_mask - bin);

+

+			if (tmp < 75)

 				mask_amt = 1;

 			else

 				mask_amt = 0;

--
[view original message]
From: Stephen Rothwell <sfr@...>
To: John W. Linville <linville@...>
Cc: Adrian Bunk <bunk@...>, <linux-next@...>, David Miller <davem@...>, LKML <linux-kernel@...>, Luis R. Rodriguez <lrodriguez@...>
Subject: Re: linux-next: wireless-current tree build failure
Date: Tuesday, August 5, 2008 - 12:35 pm

Hi John,


On Tue, 5 Aug 2008 12:00:26 -0400 "John W. Linville" <linville@tuxdriver.co=

w?


I think that "not yet" is the answer :-(


If we don't get a useful answer soon, we may just have to merge the

driver with appropriately commented negative "depends on" in Kconfig for

the arches it breaks.


--=20

Cheers,

Stephen Rothwell                    sfr@canb.auug.org.au

http://www.canb.auug.org.au/~sfr/
[view original message]
From: Stephen Rothwell <sfr@...>
To: Adrian Bunk <bunk@...>
Cc: John W. Linville <linville@...>, <linux-next@...>, David Miller <davem@...>, LKML <linux-kernel@...>, Luis R. Rodriguez <lrodriguez@...>
Subject: Re: linux-next: wireless-current tree build failure
Date: Tuesday, August 5, 2008 - 12:02 pm

Hi Adrian,


Thanks for fishing that out Adrian.

--=20

Cheers,

Stephen Rothwell                    sfr@canb.auug.org.au

http://www.canb.auug.org.au/~sfr/
Previous thread: [PATCH] X86 Architecture: HPET Rework for SB700A12 by crane cai on Tuesday, August 5, 2008 - 2:20 am. (1 message)

Next thread: [PATCH 2.6.27-rc1-git5 1/26] mdb: add include file references by jmerkey on Tuesday, August 5, 2008 - 2:26 am. (1 message)