Re: [PATCH] i2c: samsung: resume race fix
flat view
STALE5008d
REVIEWED: 1 (0M)
From: Jean Delvare <hidden>
Date: 2012-11-07 10:44:37
Also in:
linux-arm-kernel, linux-samsung-soc
1 review trailer.
On Wed, 07 Nov 2012 15:58:26 +0530, Naveen Krishna Chatradhi wrote:
Don't unmark the device as suspended until after it's been re-setup. The main race would be w.r.t. an i2c driver that gets resumed at the same time (asyncronously), that is allowed to do a transfer since suspended is set to 0 before reinit, but really should have seen the -EIO return instead.
I thought that the suspend order was children first and the resume order was parent first? If this can really happen then I am afraid this is an issue for more than just i2c-s3c2410. The proposed solution is also not really satisfactory, as the i2c client will certainly still fail to resume properly (the only improvement is that now the failure is no longer silent.)
quoted hunk ↗ jump to hunk
Signed-off-by: Olof Johansson <redacted> Signed-off-by: Naveen Krishna Chatradhi <redacted> --- drivers/i2c/busses/i2c-s3c2410.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index 3e0335f..dbaf920 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c@@ -1134,10 +1134,10 @@ static int s3c24xx_i2c_resume(struct device *dev) struct platform_device *pdev = to_platform_device(dev); struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); - i2c->suspended = 0; clk_prepare_enable(i2c->clk); s3c24xx_i2c_init(i2c); clk_disable_unprepare(i2c->clk); + i2c->suspended = 0; return 0; }
Acked-by: Jean Delvare <redacted> (Not perfect but still better than before.) -- Jean Delvare