diff options
Diffstat (limited to '0001-pwm-lpss-Fix-get_state-runtime-pm-reference-handling.patch')
| -rw-r--r-- | 0001-pwm-lpss-Fix-get_state-runtime-pm-reference-handling.patch | 100 |
1 files changed, 0 insertions, 100 deletions
diff --git a/0001-pwm-lpss-Fix-get_state-runtime-pm-reference-handling.patch b/0001-pwm-lpss-Fix-get_state-runtime-pm-reference-handling.patch deleted file mode 100644 index 1e07d8e45..000000000 --- a/0001-pwm-lpss-Fix-get_state-runtime-pm-reference-handling.patch +++ /dev/null @@ -1,100 +0,0 @@ -From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 -From: Hans de Goede <hdegoede@redhat.com> -Date: Tue, 12 May 2020 00:39:24 +0200 -Subject: [PATCH] pwm: lpss: Fix get_state runtime-pm reference handling - -Before commit cfc4c189bc70 ("pwm: Read initial hardware state at request -time"), a driver's get_state callback would get called once per PWM from -pwmchip_add(). - -pwm-lpss' runtime-pm code was relying on this, getting a runtime-pm ref for -PWMs which are enabled at probe time from within its get_state callback, -before enabling runtime-pm. - -The change to calling get_state at request time causes a number of -problems: - -1. PWMs enabled at probe time may get runtime suspended before they are -requested, causing e.g. a LCD backlight controlled by the PWM to turn off. - -2. When the request happens when the PWM has been runtime suspended, the -ctrl register will read all 1 / 0xffffffff, causing get_state to store -bogus values in the pwm_state. - -3. get_state was using an async pm_runtime_get() call, because it assumed -that runtime-pm has not been enabled yet. If shortly after the request an -apply call is made, then the pwm_lpss_is_updating() check may trigger -because the resume triggered by the pm_runtime_get() call is not complete -yet, so the ctrl register still reads all 1 / 0xffffffff. - -This commit fixes these issues by moving the initial pm_runtime_get() call -for PWMs which are enabled at probe time to the pwm_lpss_probe() function; -and by making get_state take a runtime-pm ref before reading the ctrl reg. - -BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1828927 -Fixes: cfc4c189bc70 ("pwm: Read initial hardware state at request time") -Cc: stable@vger.kernel.org -Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> -Signed-off-by: Hans de Goede <hdegoede@redhat.com> -Upstream Status: https://lore.kernel.org/linux-acpi/5f15f6bc-8650-d86e-893f-0d41557c57c7@redhat.com/ ---- - drivers/pwm/pwm-lpss.c | 15 +++++++++++---- - 1 file changed, 11 insertions(+), 4 deletions(-) - -diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c -index 75bbfe5f3bc2..9d965ffe66d1 100644 ---- a/drivers/pwm/pwm-lpss.c -+++ b/drivers/pwm/pwm-lpss.c -@@ -158,7 +158,6 @@ static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm, - return 0; - } - --/* This function gets called once from pwmchip_add to get the initial state */ - static void pwm_lpss_get_state(struct pwm_chip *chip, struct pwm_device *pwm, - struct pwm_state *state) - { -@@ -167,6 +166,8 @@ static void pwm_lpss_get_state(struct pwm_chip *chip, struct pwm_device *pwm, - unsigned long long base_unit, freq, on_time_div; - u32 ctrl; - -+ pm_runtime_get_sync(chip->dev); -+ - base_unit_range = BIT(lpwm->info->base_unit_bits); - - ctrl = pwm_lpss_read(pwm); -@@ -187,8 +188,7 @@ static void pwm_lpss_get_state(struct pwm_chip *chip, struct pwm_device *pwm, - state->polarity = PWM_POLARITY_NORMAL; - state->enabled = !!(ctrl & PWM_ENABLE); - -- if (state->enabled) -- pm_runtime_get(chip->dev); -+ pm_runtime_put(chip->dev); - } - - static const struct pwm_ops pwm_lpss_ops = { -@@ -202,7 +202,8 @@ struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r, - { - struct pwm_lpss_chip *lpwm; - unsigned long c; -- int ret; -+ int i, ret; -+ u32 ctrl; - - if (WARN_ON(info->npwm > MAX_PWMS)) - return ERR_PTR(-ENODEV); -@@ -232,6 +233,12 @@ struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r, - return ERR_PTR(ret); - } - -+ for (i = 0; i < lpwm->info->npwm; i++) { -+ ctrl = pwm_lpss_read(&lpwm->chip.pwms[i]); -+ if (ctrl & PWM_ENABLE) -+ pm_runtime_get(dev); -+ } -+ - return lpwm; - } - EXPORT_SYMBOL_GPL(pwm_lpss_probe); --- -2.26.2 - |