This is a note to let you know that I've just added the patch titled
ALSA: pxa27x: fix ac97 cold reset
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-pxa27x-fix-ac97-cold-reset.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 41b645c8624df6ace020a8863ad1449d69140f7d Mon Sep 17 00:00:00 2001
From: Mike Dunn <[email protected]>
Date: Mon, 7 Jan 2013 13:55:12 -0800
Subject: ALSA: pxa27x: fix ac97 cold reset
From: Mike Dunn <[email protected]>
commit 41b645c8624df6ace020a8863ad1449d69140f7d upstream.
Cold reset on the pxa27x currently fails and
pxa2xx_ac97_try_cold_reset: cold reset timeout (GSR=0x44)
appears in the kernel log. Through trial-and-error (the pxa270 developer's
manual is mostly incoherent on the topic of ac97 reset), I got cold reset to
complete by setting the WARM_RST bit in the GCR register (and later noticed that
pxa3xx does this for cold reset as well). Also, a timeout loop is needed to
wait for the reset to complete.
Tested on a palm treo 680 machine.
Signed-off-by: Mike Dunn <[email protected]>
Acked-by: Igor Grinberg <[email protected]>
Signed-off-by: Mark Brown <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
sound/arm/pxa2xx-ac97-lib.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/sound/arm/pxa2xx-ac97-lib.c
+++ b/sound/arm/pxa2xx-ac97-lib.c
@@ -148,6 +148,8 @@ static inline void pxa_ac97_warm_pxa27x(
static inline void pxa_ac97_cold_pxa27x(void)
{
+ unsigned int timeout;
+
GCR &= GCR_COLD_RST; /* clear everything but nCRST */
GCR &= ~GCR_COLD_RST; /* then assert nCRST */
@@ -157,8 +159,10 @@ static inline void pxa_ac97_cold_pxa27x(
clk_enable(ac97conf_clk);
udelay(5);
clk_disable(ac97conf_clk);
- GCR = GCR_COLD_RST;
- udelay(50);
+ GCR = GCR_COLD_RST | GCR_WARM_RST;
+ timeout = 100; /* wait for the codec-ready bit to be set */
+ while (!((GSR | gsr_bits) & (GSR_PCR | GSR_SCR)) && timeout--)
+ mdelay(1);
}
#endif
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/mtd-cs553x_nand-initialise-ecc.strength-before-nand_scan.patch
queue-3.4/alsa-pxa27x-fix-ac97-cold-reset.patch
queue-3.4/alsa-pxa27x-fix-ac97-warm-reset.patch
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