| Message ID | 20230424080627.20564-1-alexander.stein@ew.tq-group.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/1] i2c: imx-lpi2c: avoid taking clk_prepare mutex in PM callbacks | expand |
On Mon, Apr 24, 2023 at 10:06:27AM +0200, Alexander Stein wrote: > This is unsafe, as the runtime PM callbacks are called from the PM > workqueue, so this may deadlock when handling an i2c attached clock, > which may already hold the clk_prepare mutex from another context. > > Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com> Applied to for-current, thanks!
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c index a49b14d52a98..1af0a637d7f1 100644 --- a/drivers/i2c/busses/i2c-imx-lpi2c.c +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c @@ -639,7 +639,7 @@ static int __maybe_unused lpi2c_runtime_suspend(struct device *dev) { struct lpi2c_imx_struct *lpi2c_imx = dev_get_drvdata(dev); - clk_bulk_disable_unprepare(lpi2c_imx->num_clks, lpi2c_imx->clks); + clk_bulk_disable(lpi2c_imx->num_clks, lpi2c_imx->clks); pinctrl_pm_select_sleep_state(dev); return 0; @@ -651,7 +651,7 @@ static int __maybe_unused lpi2c_runtime_resume(struct device *dev) int ret; pinctrl_pm_select_default_state(dev); - ret = clk_bulk_prepare_enable(lpi2c_imx->num_clks, lpi2c_imx->clks); + ret = clk_bulk_enable(lpi2c_imx->num_clks, lpi2c_imx->clks); if (ret) { dev_err(dev, "failed to enable I2C clock, ret=%d\n", ret); return ret;
This is unsafe, as the runtime PM callbacks are called from the PM workqueue, so this may deadlock when handling an i2c attached clock, which may already hold the clk_prepare mutex from another context. Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com> --- This is the imx-lpi2c equivalent to commit d9a22d713acb ("i2c: imx: avoid taking clk_prepare mutex in PM callbacks"). This patch needs to be used together with [1] in order to fix the deadlock conditions. Commit message is shamlessly taken from commit d9a22d713acb. Best regards, Alexander [1] https://patchwork.ozlabs.org/project/linux-i2c/patch/20230310130815.562418-1-alexander.sverdlin@siemens.com/ drivers/i2c/busses/i2c-imx-lpi2c.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)