2015-10-16 16:02:13

by Daniel Thompson

Subject: [PATCH] hwrng: exynos - Fix unbalanced PM runtime get/puts

Currently this driver calls pm_runtime_get_sync() rampantly
but never puts anything back. This makes it impossible for the
device to autosuspend properly; it will remain fully active
after the first use.

Fix in the obvious way.

Signed-off-by: Daniel Thompson <[email protected]>
Cc: Kukjin Kim <[email protected]>
Cc: Krzysztof Kozlowski <[email protected]>
---

Notes:
Compile tested only (CONFIG_PM=y, CONFIG_HW_RANDOM_EXYNOS=m); I spotted
this whilst reviewing the code and don't have an exynos platform to
test on.

drivers/char/hw_random/exynos-rng.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/hw_random/exynos-rng.c b/drivers/char/hw_random/exynos-rng.c
index dc4701fd814f..73318e2a34dd 100644
--- a/drivers/char/hw_random/exynos-rng.c
+++ b/drivers/char/hw_random/exynos-rng.c
@@ -95,7 +95,7 @@ static int exynos_read(struct hwrng *rng, void *buf,
*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);

pm_runtime_mark_last_busy(exynos_rng->dev);
- pm_runtime_autosuspend(exynos_rng->dev);
+ pm_runtime_put_sync_autosuspend(exynos_rng->dev);

return 4;
}
--
2.4.3

2015-10-19 01:41:12

by Krzysztof Kozlowski

Subject: Re: [PATCH] hwrng: exynos - Fix unbalanced PM runtime get/puts

On 17.10.2015 01:01, Daniel Thompson wrote:
> Currently this driver calls pm_runtime_get_sync() rampantly
> but never puts anything back. This makes it impossible for the
> device to autosuspend properly; it will remain fully active
> after the first use.
>
> Fix in the obvious way.
>
> Signed-off-by: Daniel Thompson <[email protected]>
> Cc: Kukjin Kim <[email protected]>
> Cc: Krzysztof Kozlowski <[email protected]>
> ---
>
> Notes:
> Compile tested only (CONFIG_PM=y, CONFIG_HW_RANDOM_EXYNOS=m); I spotted
> this whilst reviewing the code and don't have an exynos platform to
> test on.
>
> drivers/char/hw_random/exynos-rng.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

To test the patch I had to add OF support to the driver. I have these
patches almost ready and I will send them soon. Anyway:

Tested on Trats2 board (Exynos4412):
Tested-by: Krzysztof Kozlowski <[email protected]>

Reviewed-by: Krzysztof Kozlowski <[email protected]>

Best regards,
Krzysztof

2015-10-20 14:20:06

by Herbert Xu

Subject: Re: [PATCH] hwrng: exynos - Fix unbalanced PM runtime get/puts

On Fri, Oct 16, 2015 at 05:01:51PM +0100, Daniel Thompson wrote:
> Currently this driver calls pm_runtime_get_sync() rampantly
> but never puts anything back. This makes it impossible for the
> device to autosuspend properly; it will remain fully active
> after the first use.
>
> Fix in the obvious way.
>
> Signed-off-by: Daniel Thompson <[email protected]>
> Cc: Kukjin Kim <[email protected]>
> Cc: Krzysztof Kozlowski <[email protected]>

Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt