Hi,
I've stumbled upon a problem with my tosa unit. The bootloader leaves ac97 in some partially enabled state, so when request_irq enables the AC97 irq, I see a unending storm of irq requests. I've come with the following patch (against 2.6.27, if the idea is OK, I'll rebase against 2.6.28-rc).
From: Dmitry Baryshkov dbaryshkov@gmail.com
If AC97 unit is in partially enabled state, early request_irq can trigger IRQ storm or even full hang up. Workaround this by forcibly switching ACLINK off at the start of the probe.
Signed-off-by: Dmitry Baryshkov dbaryshkov@gmail.com --- sound/soc/pxa/pxa2xx-ac97.c | 30 +++++++++++++++++------------- 1 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/sound/soc/pxa/pxa2xx-ac97.c b/sound/soc/pxa/pxa2xx-ac97.c index d94a495..259c6e1 100644 --- a/sound/soc/pxa/pxa2xx-ac97.c +++ b/sound/soc/pxa/pxa2xx-ac97.c @@ -315,10 +315,6 @@ static int pxa2xx_ac97_probe(struct platform_device *pdev, { int ret;
- ret = request_irq(IRQ_AC97, pxa2xx_ac97_irq, IRQF_DISABLED, "AC97", NULL); - if (ret < 0) - goto err; - pxa_gpio_mode(GPIO31_SYNC_AC97_MD); pxa_gpio_mode(GPIO30_SDATA_OUT_AC97_MD); pxa_gpio_mode(GPIO28_BITCLK_AC97_MD); @@ -331,28 +327,36 @@ static int pxa2xx_ac97_probe(struct platform_device *pdev, if (IS_ERR(ac97conf_clk)) { ret = PTR_ERR(ac97conf_clk); ac97conf_clk = NULL; - goto err_irq; + goto err_conf; } #endif + GCR = GCR_ACLINK_OFF; + ac97_clk = clk_get(&pdev->dev, "AC97CLK"); if (IS_ERR(ac97_clk)) { ret = PTR_ERR(ac97_clk); ac97_clk = NULL; - goto err_irq; + goto err_clk; } clk_enable(ac97_clk); + + ret = request_irq(IRQ_AC97, pxa2xx_ac97_irq, IRQF_DISABLED, "AC97", NULL); + if (ret < 0) + goto err_irq; + return 0;
- err_irq: +err_irq: GCR |= GCR_ACLINK_OFF; + clk_disable(ac97_clk); + clk_put(ac97_clk); + ac97_clk = NULL; +err_clk: #ifdef CONFIG_PXA27x - if (ac97conf_clk) { - clk_put(ac97conf_clk); - ac97conf_clk = NULL; - } + clk_put(ac97conf_clk); + ac97conf_clk = NULL; +err_conf: #endif - free_irq(IRQ_AC97, NULL); - err: return ret; }