| Message ID | 20200708211432.28612-17-hdegoede@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | acpi/pwm/i915: Convert pwm-crc and i915 driver's PWM code to use the atomic PWM API | expand |
On Wed, Jul 08, 2020 at 11:14:32PM +0200, Hans de Goede wrote: > Now that the PWM drivers which we use have been converted to the atomic > PWM API, we can move the i915 panel code over to using the atomic PWM API. > > The removes a long standing FIXME and this removes a flicker where > the backlight brightness would jump to 100% when i915 loads even if > using the fastset path. > > Note that this commit also simplifies pwm_disable_backlight(), by dropping > the intel_panel_actually_set_backlight(..., 0) call. This call sets the > PWM to 0% duty-cycle. I believe that this call was only present as a > workaround for a bug in the pwm-crc.c driver where it failed to clear the > PWM_OUTPUT_ENABLE bit. This is fixed by an earlier patch in this series. > > After the dropping of this workaround, the usleep call, which seems > unnecessary to begin with, has no useful effect anymore, so drop that too. > > Acked-by: Jani Nikula <jani.nikula@intel.com> > Signed-off-by: Hans de Goede <hdegoede@redhat.com> > --- > Changes in v4: > - Add a note to the commit message about the dropping of the > intel_panel_actually_set_backlight() and usleep() calls from > pwm_disable_backlight() > - Use the pwm_set/get_relative_duty_cycle() helpers instead of using DIY code > for this > --- > .../drm/i915/display/intel_display_types.h | 3 +- > drivers/gpu/drm/i915/display/intel_panel.c | 71 +++++++++---------- > 2 files changed, 34 insertions(+), 40 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h > index de32f9efb120..4bd9981e70a1 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_types.h > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h > @@ -28,6 +28,7 @@ > > #include <linux/async.h> > #include <linux/i2c.h> > +#include <linux/pwm.h> > #include <linux/sched/clock.h> > > #include <drm/drm_atomic.h> > @@ -223,7 +224,7 @@ struct intel_panel { > bool util_pin_active_low; /* bxt+ */ > u8 controller; /* bxt+ only */ > struct pwm_device *pwm; > - int pwm_period_ns; > + struct pwm_state pwm_state; > > /* DPCD backlight */ > u8 pwmgen_bit_count; > diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c > index cb28b9908ca4..3d97267c8238 100644 > --- a/drivers/gpu/drm/i915/display/intel_panel.c > +++ b/drivers/gpu/drm/i915/display/intel_panel.c > @@ -592,10 +592,10 @@ static u32 bxt_get_backlight(struct intel_connector *connector) > static u32 pwm_get_backlight(struct intel_connector *connector) > { > struct intel_panel *panel = &connector->panel; > - int duty_ns; > + struct pwm_state state; > > - duty_ns = pwm_get_duty_cycle(panel->backlight.pwm); > - return DIV_ROUND_UP(duty_ns * 100, panel->backlight.pwm_period_ns); > + pwm_get_state(panel->backlight.pwm, &state); > + return pwm_get_relative_duty_cycle(&state, 100); Here you introduce a slight difference: pwm_get_relative_duty_cycle uses round-closest while you replace a round-up. Is this relevant? > } > > static void lpt_set_backlight(const struct drm_connector_state *conn_state, u32 level) > @@ -669,10 +669,9 @@ static void bxt_set_backlight(const struct drm_connector_state *conn_state, u32 > static void pwm_set_backlight(const struct drm_connector_state *conn_state, u32 level) > { > struct intel_panel *panel = &to_intel_connector(conn_state->connector)->panel; > - int duty_ns = DIV_ROUND_UP(level * panel->backlight.pwm_period_ns, 100); > > - pwm_config(panel->backlight.pwm, duty_ns, > - panel->backlight.pwm_period_ns); > + pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100); > + pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state); Similar here: The function used to use round-up but pwm_set_relative_duty_cycle() used round-closest. > } > > static void > @@ -841,10 +840,8 @@ static void pwm_disable_backlight(const struct drm_connector_state *old_conn_sta > struct intel_connector *connector = to_intel_connector(old_conn_state->connector); > struct intel_panel *panel = &connector->panel; > > - /* Disable the backlight */ > - intel_panel_actually_set_backlight(old_conn_state, 0); > - usleep_range(2000, 3000); > - pwm_disable(panel->backlight.pwm); > + panel->backlight.pwm_state.enabled = false; > + pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state); > } > > void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state) > @@ -1176,9 +1173,12 @@ static void pwm_enable_backlight(const struct intel_crtc_state *crtc_state, > { > struct intel_connector *connector = to_intel_connector(conn_state->connector); > struct intel_panel *panel = &connector->panel; > + int level = panel->backlight.level; > > - pwm_enable(panel->backlight.pwm); > - intel_panel_actually_set_backlight(conn_state, panel->backlight.level); > + level = intel_panel_compute_brightness(connector, level); > + pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100); > + panel->backlight.pwm_state.enabled = true; > + pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state); > } > > static void __intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state, > @@ -1897,8 +1897,7 @@ static int pwm_setup_backlight(struct intel_connector *connector, > struct drm_i915_private *dev_priv = to_i915(dev); > struct intel_panel *panel = &connector->panel; > const char *desc; > - u32 level, ns; > - int retval; > + u32 level; > > /* Get the right PWM chip for DSI backlight according to VBT */ > if (dev_priv->vbt.dsi.config->pwm_blc == PPS_BLC_PMIC) { > @@ -1916,36 +1915,30 @@ static int pwm_setup_backlight(struct intel_connector *connector, > return -ENODEV; > } > > - panel->backlight.pwm_period_ns = NSEC_PER_SEC / > - get_vbt_pwm_freq(dev_priv); > - > - /* > - * FIXME: pwm_apply_args() should be removed when switching to > - * the atomic PWM API. > - */ > - pwm_apply_args(panel->backlight.pwm); > - > panel->backlight.max = 100; /* 100% */ > panel->backlight.min = get_backlight_min_vbt(connector); > - level = intel_panel_compute_brightness(connector, 100); > - ns = DIV_ROUND_UP(level * panel->backlight.pwm_period_ns, 100); > > - retval = pwm_config(panel->backlight.pwm, ns, > - panel->backlight.pwm_period_ns); > - if (retval < 0) { > - drm_err(&dev_priv->drm, "Failed to configure the pwm chip\n"); > - pwm_put(panel->backlight.pwm); > - panel->backlight.pwm = NULL; > - return retval; > + if (pwm_is_enabled(panel->backlight.pwm) && > + pwm_get_period(panel->backlight.pwm)) { What would pwm_is_enabled(panel->backlight.pwm) == true && pwm_get_period(panel->backlight.pwm) == 0 mean? I hope this doesn't happen?! > + /* PWM is already enabled, use existing settings */ > + pwm_get_state(panel->backlight.pwm, &panel->backlight.pwm_state); > + > + level = pwm_get_relative_duty_cycle(&panel->backlight.pwm_state, > + 100); > + level = intel_panel_compute_brightness(connector, level); > + panel->backlight.level = clamp(level, panel->backlight.min, > + panel->backlight.max); > + panel->backlight.enabled = true; > + > + drm_dbg_kms(&dev_priv->drm, "PWM already enabled at freq %ld, VBT freq %d, level %d\n", > + NSEC_PER_SEC / panel->backlight.pwm_state.period, .period becomes a u64 soon, so be prepared to fixup here. > + get_vbt_pwm_freq(dev_priv), level); > + } else { > + /* Set period from VBT frequency, leave other settings at 0. */ > + panel->backlight.pwm_state.period = > + NSEC_PER_SEC / get_vbt_pwm_freq(dev_priv); > } > > - level = DIV_ROUND_UP(pwm_get_duty_cycle(panel->backlight.pwm) * 100, > - panel->backlight.pwm_period_ns); > - level = intel_panel_compute_brightness(connector, level); > - panel->backlight.level = clamp(level, panel->backlight.min, > - panel->backlight.max); > - panel->backlight.enabled = panel->backlight.level != 0; > - > drm_info(&dev_priv->drm, "Using %s PWM for LCD backlight control\n", > desc); > return 0; Best regards Uwe
Hi, On 7/11/20 8:32 AM, Uwe Kleine-König wrote: > On Wed, Jul 08, 2020 at 11:14:32PM +0200, Hans de Goede wrote: >> Now that the PWM drivers which we use have been converted to the atomic >> PWM API, we can move the i915 panel code over to using the atomic PWM API. >> >> The removes a long standing FIXME and this removes a flicker where >> the backlight brightness would jump to 100% when i915 loads even if >> using the fastset path. >> >> Note that this commit also simplifies pwm_disable_backlight(), by dropping >> the intel_panel_actually_set_backlight(..., 0) call. This call sets the >> PWM to 0% duty-cycle. I believe that this call was only present as a >> workaround for a bug in the pwm-crc.c driver where it failed to clear the >> PWM_OUTPUT_ENABLE bit. This is fixed by an earlier patch in this series. >> >> After the dropping of this workaround, the usleep call, which seems >> unnecessary to begin with, has no useful effect anymore, so drop that too. >> >> Acked-by: Jani Nikula <jani.nikula@intel.com> >> Signed-off-by: Hans de Goede <hdegoede@redhat.com> >> --- >> Changes in v4: >> - Add a note to the commit message about the dropping of the >> intel_panel_actually_set_backlight() and usleep() calls from >> pwm_disable_backlight() >> - Use the pwm_set/get_relative_duty_cycle() helpers instead of using DIY code >> for this >> --- >> .../drm/i915/display/intel_display_types.h | 3 +- >> drivers/gpu/drm/i915/display/intel_panel.c | 71 +++++++++---------- >> 2 files changed, 34 insertions(+), 40 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h >> index de32f9efb120..4bd9981e70a1 100644 >> --- a/drivers/gpu/drm/i915/display/intel_display_types.h >> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h >> @@ -28,6 +28,7 @@ >> >> #include <linux/async.h> >> #include <linux/i2c.h> >> +#include <linux/pwm.h> >> #include <linux/sched/clock.h> >> >> #include <drm/drm_atomic.h> >> @@ -223,7 +224,7 @@ struct intel_panel { >> bool util_pin_active_low; /* bxt+ */ >> u8 controller; /* bxt+ only */ >> struct pwm_device *pwm; >> - int pwm_period_ns; >> + struct pwm_state pwm_state; >> >> /* DPCD backlight */ >> u8 pwmgen_bit_count; >> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c >> index cb28b9908ca4..3d97267c8238 100644 >> --- a/drivers/gpu/drm/i915/display/intel_panel.c >> +++ b/drivers/gpu/drm/i915/display/intel_panel.c >> @@ -592,10 +592,10 @@ static u32 bxt_get_backlight(struct intel_connector *connector) >> static u32 pwm_get_backlight(struct intel_connector *connector) >> { >> struct intel_panel *panel = &connector->panel; >> - int duty_ns; >> + struct pwm_state state; >> >> - duty_ns = pwm_get_duty_cycle(panel->backlight.pwm); >> - return DIV_ROUND_UP(duty_ns * 100, panel->backlight.pwm_period_ns); >> + pwm_get_state(panel->backlight.pwm, &state); >> + return pwm_get_relative_duty_cycle(&state, 100); > > Here you introduce a slight difference: pwm_get_relative_duty_cycle uses > round-closest while you replace a round-up. Is this relevant? Yes I'm aware of the change in rounding and I do not believe that it is relevant. One of the advantages of switching to the helpers is not having to worry about the rounding and letting the helpers figure that out :) >> } >> >> static void lpt_set_backlight(const struct drm_connector_state *conn_state, u32 level) >> @@ -669,10 +669,9 @@ static void bxt_set_backlight(const struct drm_connector_state *conn_state, u32 >> static void pwm_set_backlight(const struct drm_connector_state *conn_state, u32 level) >> { >> struct intel_panel *panel = &to_intel_connector(conn_state->connector)->panel; >> - int duty_ns = DIV_ROUND_UP(level * panel->backlight.pwm_period_ns, 100); >> >> - pwm_config(panel->backlight.pwm, duty_ns, >> - panel->backlight.pwm_period_ns); >> + pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100); >> + pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state); > > Similar here: The function used to use round-up but > pwm_set_relative_duty_cycle() used round-closest. Idem. >> } >> >> static void >> @@ -841,10 +840,8 @@ static void pwm_disable_backlight(const struct drm_connector_state *old_conn_sta >> struct intel_connector *connector = to_intel_connector(old_conn_state->connector); >> struct intel_panel *panel = &connector->panel; >> >> - /* Disable the backlight */ >> - intel_panel_actually_set_backlight(old_conn_state, 0); >> - usleep_range(2000, 3000); >> - pwm_disable(panel->backlight.pwm); >> + panel->backlight.pwm_state.enabled = false; >> + pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state); >> } >> >> void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state) >> @@ -1176,9 +1173,12 @@ static void pwm_enable_backlight(const struct intel_crtc_state *crtc_state, >> { >> struct intel_connector *connector = to_intel_connector(conn_state->connector); >> struct intel_panel *panel = &connector->panel; >> + int level = panel->backlight.level; >> >> - pwm_enable(panel->backlight.pwm); >> - intel_panel_actually_set_backlight(conn_state, panel->backlight.level); >> + level = intel_panel_compute_brightness(connector, level); >> + pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100); >> + panel->backlight.pwm_state.enabled = true; >> + pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state); >> } >> >> static void __intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state, >> @@ -1897,8 +1897,7 @@ static int pwm_setup_backlight(struct intel_connector *connector, >> struct drm_i915_private *dev_priv = to_i915(dev); >> struct intel_panel *panel = &connector->panel; >> const char *desc; >> - u32 level, ns; >> - int retval; >> + u32 level; >> >> /* Get the right PWM chip for DSI backlight according to VBT */ >> if (dev_priv->vbt.dsi.config->pwm_blc == PPS_BLC_PMIC) { >> @@ -1916,36 +1915,30 @@ static int pwm_setup_backlight(struct intel_connector *connector, >> return -ENODEV; >> } >> >> - panel->backlight.pwm_period_ns = NSEC_PER_SEC / >> - get_vbt_pwm_freq(dev_priv); >> - >> - /* >> - * FIXME: pwm_apply_args() should be removed when switching to >> - * the atomic PWM API. >> - */ >> - pwm_apply_args(panel->backlight.pwm); >> - >> panel->backlight.max = 100; /* 100% */ >> panel->backlight.min = get_backlight_min_vbt(connector); >> - level = intel_panel_compute_brightness(connector, 100); >> - ns = DIV_ROUND_UP(level * panel->backlight.pwm_period_ns, 100); >> >> - retval = pwm_config(panel->backlight.pwm, ns, >> - panel->backlight.pwm_period_ns); >> - if (retval < 0) { >> - drm_err(&dev_priv->drm, "Failed to configure the pwm chip\n"); >> - pwm_put(panel->backlight.pwm); >> - panel->backlight.pwm = NULL; >> - return retval; >> + if (pwm_is_enabled(panel->backlight.pwm) && >> + pwm_get_period(panel->backlight.pwm)) { > > What would pwm_is_enabled(panel->backlight.pwm) == true && > pwm_get_period(panel->backlight.pwm) == 0 mean? I hope this doesn't > happen?! It shouldn't happen this code uses only 2 PWM controller drivers, pwm-crc and pwm-lpss and the get_state of neither ever sets period tto 0. This check is just here for extra safety, since getting it wrong would lead to a divide by 0. Which I see has been fixed by the helper now (which does its own period==0 check). So I guess I can (and I will) just drop this extra check for the next version. >> + /* PWM is already enabled, use existing settings */ >> + pwm_get_state(panel->backlight.pwm, &panel->backlight.pwm_state); >> + >> + level = pwm_get_relative_duty_cycle(&panel->backlight.pwm_state, >> + 100); >> + level = intel_panel_compute_brightness(connector, level); >> + panel->backlight.level = clamp(level, panel->backlight.min, >> + panel->backlight.max); >> + panel->backlight.enabled = true; >> + >> + drm_dbg_kms(&dev_priv->drm, "PWM already enabled at freq %ld, VBT freq %d, level %d\n", >> + NSEC_PER_SEC / panel->backlight.pwm_state.period, > > .period becomes a u64 soon, so be prepared to fixup here. > >> + get_vbt_pwm_freq(dev_priv), level); >> + } else { >> + /* Set period from VBT frequency, leave other settings at 0. */ >> + panel->backlight.pwm_state.period = >> + NSEC_PER_SEC / get_vbt_pwm_freq(dev_priv); >> } >> >> - level = DIV_ROUND_UP(pwm_get_duty_cycle(panel->backlight.pwm) * 100, >> - panel->backlight.pwm_period_ns); >> - level = intel_panel_compute_brightness(connector, level); >> - panel->backlight.level = clamp(level, panel->backlight.min, >> - panel->backlight.max); >> - panel->backlight.enabled = panel->backlight.level != 0; >> - >> drm_info(&dev_priv->drm, "Using %s PWM for LCD backlight control\n", >> desc); >> return 0; > > Best regards > Uwe Regards, Hans
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h index de32f9efb120..4bd9981e70a1 100644 --- a/drivers/gpu/drm/i915/display/intel_display_types.h +++ b/drivers/gpu/drm/i915/display/intel_display_types.h @@ -28,6 +28,7 @@ #include <linux/async.h> #include <linux/i2c.h> +#include <linux/pwm.h> #include <linux/sched/clock.h> #include <drm/drm_atomic.h> @@ -223,7 +224,7 @@ struct intel_panel { bool util_pin_active_low; /* bxt+ */ u8 controller; /* bxt+ only */ struct pwm_device *pwm; - int pwm_period_ns; + struct pwm_state pwm_state; /* DPCD backlight */ u8 pwmgen_bit_count; diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c index cb28b9908ca4..3d97267c8238 100644 --- a/drivers/gpu/drm/i915/display/intel_panel.c +++ b/drivers/gpu/drm/i915/display/intel_panel.c @@ -592,10 +592,10 @@ static u32 bxt_get_backlight(struct intel_connector *connector) static u32 pwm_get_backlight(struct intel_connector *connector) { struct intel_panel *panel = &connector->panel; - int duty_ns; + struct pwm_state state; - duty_ns = pwm_get_duty_cycle(panel->backlight.pwm); - return DIV_ROUND_UP(duty_ns * 100, panel->backlight.pwm_period_ns); + pwm_get_state(panel->backlight.pwm, &state); + return pwm_get_relative_duty_cycle(&state, 100); } static void lpt_set_backlight(const struct drm_connector_state *conn_state, u32 level) @@ -669,10 +669,9 @@ static void bxt_set_backlight(const struct drm_connector_state *conn_state, u32 static void pwm_set_backlight(const struct drm_connector_state *conn_state, u32 level) { struct intel_panel *panel = &to_intel_connector(conn_state->connector)->panel; - int duty_ns = DIV_ROUND_UP(level * panel->backlight.pwm_period_ns, 100); - pwm_config(panel->backlight.pwm, duty_ns, - panel->backlight.pwm_period_ns); + pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100); + pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state); } static void @@ -841,10 +840,8 @@ static void pwm_disable_backlight(const struct drm_connector_state *old_conn_sta struct intel_connector *connector = to_intel_connector(old_conn_state->connector); struct intel_panel *panel = &connector->panel; - /* Disable the backlight */ - intel_panel_actually_set_backlight(old_conn_state, 0); - usleep_range(2000, 3000); - pwm_disable(panel->backlight.pwm); + panel->backlight.pwm_state.enabled = false; + pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state); } void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state) @@ -1176,9 +1173,12 @@ static void pwm_enable_backlight(const struct intel_crtc_state *crtc_state, { struct intel_connector *connector = to_intel_connector(conn_state->connector); struct intel_panel *panel = &connector->panel; + int level = panel->backlight.level; - pwm_enable(panel->backlight.pwm); - intel_panel_actually_set_backlight(conn_state, panel->backlight.level); + level = intel_panel_compute_brightness(connector, level); + pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100); + panel->backlight.pwm_state.enabled = true; + pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state); } static void __intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state, @@ -1897,8 +1897,7 @@ static int pwm_setup_backlight(struct intel_connector *connector, struct drm_i915_private *dev_priv = to_i915(dev); struct intel_panel *panel = &connector->panel; const char *desc; - u32 level, ns; - int retval; + u32 level; /* Get the right PWM chip for DSI backlight according to VBT */ if (dev_priv->vbt.dsi.config->pwm_blc == PPS_BLC_PMIC) { @@ -1916,36 +1915,30 @@ static int pwm_setup_backlight(struct intel_connector *connector, return -ENODEV; } - panel->backlight.pwm_period_ns = NSEC_PER_SEC / - get_vbt_pwm_freq(dev_priv); - - /* - * FIXME: pwm_apply_args() should be removed when switching to - * the atomic PWM API. - */ - pwm_apply_args(panel->backlight.pwm); - panel->backlight.max = 100; /* 100% */ panel->backlight.min = get_backlight_min_vbt(connector); - level = intel_panel_compute_brightness(connector, 100); - ns = DIV_ROUND_UP(level * panel->backlight.pwm_period_ns, 100); - retval = pwm_config(panel->backlight.pwm, ns, - panel->backlight.pwm_period_ns); - if (retval < 0) { - drm_err(&dev_priv->drm, "Failed to configure the pwm chip\n"); - pwm_put(panel->backlight.pwm); - panel->backlight.pwm = NULL; - return retval; + if (pwm_is_enabled(panel->backlight.pwm) && + pwm_get_period(panel->backlight.pwm)) { + /* PWM is already enabled, use existing settings */ + pwm_get_state(panel->backlight.pwm, &panel->backlight.pwm_state); + + level = pwm_get_relative_duty_cycle(&panel->backlight.pwm_state, + 100); + level = intel_panel_compute_brightness(connector, level); + panel->backlight.level = clamp(level, panel->backlight.min, + panel->backlight.max); + panel->backlight.enabled = true; + + drm_dbg_kms(&dev_priv->drm, "PWM already enabled at freq %ld, VBT freq %d, level %d\n", + NSEC_PER_SEC / panel->backlight.pwm_state.period, + get_vbt_pwm_freq(dev_priv), level); + } else { + /* Set period from VBT frequency, leave other settings at 0. */ + panel->backlight.pwm_state.period = + NSEC_PER_SEC / get_vbt_pwm_freq(dev_priv); } - level = DIV_ROUND_UP(pwm_get_duty_cycle(panel->backlight.pwm) * 100, - panel->backlight.pwm_period_ns); - level = intel_panel_compute_brightness(connector, level); - panel->backlight.level = clamp(level, panel->backlight.min, - panel->backlight.max); - panel->backlight.enabled = panel->backlight.level != 0; - drm_info(&dev_priv->drm, "Using %s PWM for LCD backlight control\n", desc); return 0;