If PWM device is requested by means of legacy API pwm_request(), its resources are not freed on module unbind, which may cause an oops on access, e.g. by reading /sys/kernel/debug/pwm.
Reported-by: Dmitry Eremin-Solenikov <[email protected]> Signed-off-by: Vladimir Zapolskiy <[email protected]> --- drivers/video/backlight/pwm_bl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index dd7aaf7..40770dd 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -34,6 +34,7 @@ struct pwm_bl_data { struct regulator *power_supply; struct gpio_desc *enable_gpio; unsigned int scale; + bool legacy; int (*notify)(struct device *, int brightness); void (*notify_after)(struct device *, @@ -274,6 +275,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->pwm = devm_pwm_get(&pdev->dev, NULL); if (IS_ERR(pb->pwm) && !pdev->dev.of_node) { dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); + pb->legacy = true; pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); } @@ -339,6 +341,8 @@ static int pwm_backlight_remove(struct platform_device *pdev) if (pb->exit) pb->exit(&pdev->dev); + if (pb->legacy) + pwm_free(pb->pwm); return 0; } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
