Re: [PATCH] drm/i915: Backlight Control over AUX feature

Daniel Vetter
2015-09-14T17:15:38Z

On Mon, Sep 14, 2015 at 04:29:05PM +0000, Adebisi, YetundeX wrote:
>
>
> > -----Original Message-----
> > From: Daniel Vetter [mailto:daniel.vetter@ffwll.ch] On Behalf Of Daniel
> > Vetter
> > Sent: Thursday, September 10, 2015 4:21 PM
> > To: Adebisi, YetundeX
> > Cc: Intel-gfx@lists.freedesktop.org
> > Subject: Re: [Intel-gfx] [PATCH] drm/i915: Backlight Control over AUX feature
> >
> > On Thu, Sep 10, 2015 at 03:11:42PM +0100, Yetunde Adebisi wrote:
> > > This patch adds support for Backlight Control over the AUX channel for
> > > DP and eDP connectors. It allows the backlight of DP and eDP connected
> > > displays to be controlled from software using sysfs interface.
> > >
> > > The code first checks if the DP/eDP display has the capability for
> > > backlight control by reading Display Control DPCD registers as defined
> > > by the eDP v1.3 VESA specs.
> > > It then registers a /sys/backlight device if backlight control is
> > > supported.
> > >
> > > It provides functions to
> > > - Register a sysfs backlight interface if the eDP/DP connnector is
> > > capable of aux backlight control
> > > - Read the current backlight level from DPCD register 0x722
> > > - Change the backlight level
> > > - Disable/Enable the backlight by writing to DPCD register 0x720
> > >
> > > Usage:
> > > Backlight level ranges from 0(min)-240(max) 0x0-0xF0
> > > - To change Backlight level to 50
> > > echo 50 > /sys/class/backlight/intel_aux_backlight-DP-3/brightness
> > >
> > > - To disable backlight
> > > echo 4 > /sys/class/backlight/intel_aux_backlight-DP-3/bl_power
> > > - To enable backlight
> > > echo 0 > /sys/class/backlight/intel_aux_backlight-DP-3/bl_power
> > >
> > > v2:
> > > - Code clean up
> > > - Avoid code duplication by merging the backlight device
> > > register/unregister function with the existing one for internal
> > > displays
> > >
> > > v3:
> > > Further changes to re-use existing code by adding bl_name and
> > > backlight_ops variables to the intel_backlight structure.
> > >
> > > Cc: Bob Paauwe <bob.j.paauwe@intel.com>
> > > Signed-off-by: Yetunde Adebisi <yetundex.adebisi@intel.com>
> > > ---
> > > drivers/gpu/drm/i915/Makefile | 1 +
> > > drivers/gpu/drm/i915/intel_display.c | 1 +
> > > drivers/gpu/drm/i915/intel_dp.c | 6 +-
> > > drivers/gpu/drm/i915/intel_dp_aux_backlight_ctl.c | 324
> > ++++++++++++++++++++++
> > > drivers/gpu/drm/i915/intel_drv.h | 46 ++-
> > > drivers/gpu/drm/i915/intel_panel.c | 111 +++++---
> > > include/drm/drm_dp_helper.h | 6 +
> > > 7 files changed, 443 insertions(+), 52 deletions(-) create mode
> > > 100644 drivers/gpu/drm/i915/intel_dp_aux_backlight_ctl.c
> > >
> > > diff --git a/drivers/gpu/drm/i915/Makefile
> > > b/drivers/gpu/drm/i915/Makefile index 44d290a..260be03 100644
> > > --- a/drivers/gpu/drm/i915/Makefile
> > > +++ b/drivers/gpu/drm/i915/Makefile
> > > @@ -77,6 +77,7 @@ i915-y += dvo_ch7017.o \
> > > dvo_tfp410.o \
> > > intel_crt.o \
> > > intel_ddi.o \
> > > + intel_dp_aux_backlight_ctl.o \
> >
> > Shouldn't we have most of this implemented as a generic helper on top of
> > the core drm_dp_aux abstraction in the drm_dp_helper.c code? And drivers
> > would then just call the overall backlight_register/unregister functions
> > provided by those helpers.
> I can see that it makes sense to add helper functions for getting and setting the backlight values.
>
> Can you please clarify what you mean about the backlight_register/unregister functions?
>
> Apologies if this is obvious.

See Jani's latest mail with the outcome from the irc discussion I had with
Jani and what the plan is. My mail here is before that discussion, so you
can entirely disregard it.

Thanks, Daniel

>
> Thank you.
> >
> > The other bit from my high-level review is that the kerneldoc needs more
> > polish and needs to be pulled into drm.tmpl at a suitable place.
> > -Daniel
> >
> > > intel_dp_mst.o \
> > > intel_dp.o \
> > > intel_dsi.o \
> > > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > > b/drivers/gpu/drm/i915/intel_display.c
> > > index e629a1b..2937432 100644
> > > --- a/drivers/gpu/drm/i915/intel_display.c
> > > +++ b/drivers/gpu/drm/i915/intel_display.c
> > > @@ -15340,6 +15340,7 @@ void intel_connector_unregister(struct
> > intel_connector *intel_connector)
> > > struct drm_connector *connector = &intel_connector->base;
> > >
> > > intel_panel_destroy_backlight(connector);
> > > + intel_dp_aux_backlight_destroy(connector);
> > > drm_connector_unregister(connector);
> > > }
> > >
> > > diff --git a/drivers/gpu/drm/i915/intel_dp.c
> > > b/drivers/gpu/drm/i915/intel_dp.c index 45ab25e..975a836 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > @@ -3018,7 +3018,7 @@ static void chv_dp_post_pll_disable(struct
> > intel_encoder *encoder)
> > > * Sinks are *supposed* to come up within 1ms from an off state, but
> > we're also
> > > * supposed to retry 3 times per the spec.
> > > */
> > > -static ssize_t
> > > +ssize_t
> > > intel_dp_dpcd_read_wake(struct drm_dp_aux *aux, unsigned int offset,
> > > void *buffer, size_t size)
> > > {
> > > @@ -3969,7 +3969,7 @@ intel_dp_link_down(struct intel_dp *intel_dp)
> > > msleep(intel_dp->panel_power_down_delay);
> > > }
> > >
> > > -static bool
> > > +bool
> > > intel_dp_get_dpcd(struct intel_dp *intel_dp) {
> > > struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp); @@
> > > -6125,6 +6125,8 @@ intel_dp_init_connector(struct intel_digital_port
> > *intel_dig_port,
> > > return false;
> > > }
> > >
> > > + intel_dp_aux_backlight_init(intel_dp, connector);
> > > +
> > > intel_dp_add_properties(intel_dp, connector);
> > >
> > > /* For G4X desktop chip, PEG_BAND_GAP_DATA 3:0 must first be
> > written
> > > diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight_ctl.c
> > > b/drivers/gpu/drm/i915/intel_dp_aux_backlight_ctl.c
> > > new file mode 100644
> > > index 0000000..a8ef960
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight_ctl.c
> > > @@ -0,0 +1,324 @@
> > > +/*
> > > + * Copyright (c) 2015 Intel Corporation
> > > + *
> > > + * Permission is hereby granted, free of charge, to any person
> > > +obtaining a
> > > + * copy of this software and associated documentation files (the
> > > +"Software"),
> > > + * to deal in the Software without restriction, including without
> > > +limitation
> > > + * the rights to use, copy, modify, merge, publish, distribute,
> > > +sublicense,
> > > + * and/or sell copies of the Software, and to permit persons to whom
> > > +the
> > > + * Software is furnished to do so, subject to the following conditions:
> > > + *
> > > + * The above copyright notice and this permission notice (including
> > > +the next
> > > + * paragraph) shall be included in all copies or substantial portions
> > > +of the
> > > + * Software.
> > > + *
> > > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
> > KIND,
> > > +EXPRESS OR
> > > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> > > +MERCHANTABILITY,
> > > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
> > NO EVENT
> > > +SHALL
> > > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
> > DAMAGES
> > > +OR OTHER
> > > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
> > OTHERWISE,
> > > +ARISING
> > > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
> > OR
> > > +OTHER DEALINGS
> > > + * IN THE SOFTWARE.
> > > + *
> > > + *
> > > + */
> > > +
> > > +#include "intel_drv.h"
> > > +
> > > +
> > > +#define MAX_AUX_BL_HW_LEVEL 0xF0
> > > +#define MIN_AUX_BL_HW_LEVEL 0x00
> > > +
> > > +
> > > +static uint8_t read_mode_set_reg(struct intel_dp *intel_dp) {
> > > + uint8_t dpcd_buf = 0;
> > > +
> > > + if (intel_dp_dpcd_read_wake(&intel_dp->aux,
> > > + DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
> > > + &dpcd_buf, sizeof(dpcd_buf)) < 0)
> > > + DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
> > > + DP_EDP_BACKLIGHT_MODE_SET_REGISTER);
> > > +
> > > + return dpcd_buf;
> > > +}
> > > +
> > > +/**
> > > + * Read the current backlight value from DPCD register(s) based
> > > + * on if 8-bit(MSB) or 16-bit(MSB and LSB) values are supported */
> > > +static uint16_t read_aux_backlight_level(struct intel_dp *intel_dp) {
> > > + uint16_t read_val = 0;
> > > +
> > > + if (intel_dp_dpcd_read_wake(&intel_dp->aux,
> > > + DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
> > > + &read_val, sizeof(read_val)) < 0) {
> > > + DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
> > > + DP_EDP_BACKLIGHT_BRIGHTNESS_MSB);
> > > + return 0;
> > > + }
> > > + if (intel_dp->aux_backlight.use_lsb_reg) {
> > > + uint8_t val_lsb = 0;
> > > +
> > > + if (intel_dp_dpcd_read_wake(&intel_dp->aux,
> > > + DP_EDP_BACKLIGHT_BRIGHTNESS_LSB,
> > > + &val_lsb, sizeof(val_lsb)) < 0) {
> > > + DRM_DEBUG_KMS("Failed to read DPCD register
> > 0x%x\n",
> > > +
> > DP_EDP_BACKLIGHT_BRIGHTNESS_LSB);
> > > + return 0;
> > > + }
> > > + read_val = (read_val << 8 | val_lsb);
> > > + }
> > > +
> > > + return read_val;
> > > +}
> > > +
> > > +
> > > +static bool get_aux_backlight_enable(struct drm_dp_aux *aux) {
> > > + uint8_t read_val = 0;
> > > +
> > > + if (intel_dp_dpcd_read_wake(aux,
> > DP_EDP_DISPLAY_CONTROL_REGISTER,
> > > + &read_val, sizeof(read_val)) < 0) {
> > > + DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
> > > + DP_EDP_DISPLAY_CONTROL_REGISTER);
> > > + }
> > > + return read_val & DP_EDP_BACKLIGHT_ENABLE; }
> > > +
> > > +
> > > +static bool is_aux_display_control_capable(struct drm_connector
> > > +*connector) {
> > > + struct intel_encoder *intel_encoder =
> > intel_attached_encoder(connector);
> > > + struct intel_dp *intel_dp = enc_to_intel_dp(&intel_encoder->base);
> > > + uint8_t dpcd_edp[2] = { 0x0 };
> > > +
> > > + /* Check the eDP Display control capabilities registers to determine if
> > > + * the panel can support backlight control over the aux channel*/
> > > + if (intel_dp_dpcd_read_wake(&intel_dp->aux,
> > DP_EDP_GENERAL_CAP_1,
> > > + dpcd_edp, sizeof(dpcd_edp)) < 0) {
> > > + DRM_DEBUG_KMS("Failed to read DPCD Display Control
> > registers\n");
> > > + return false;
> > > + }
> > > + DRM_DEBUG_KMS("EDP DPCD : %*ph\n", (int) sizeof(dpcd_edp),
> > > +dpcd_edp);
> > > +
> > > + if (dpcd_edp[0] &
> > DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAPABLE &&
> > > + (dpcd_edp[0] &
> > DP_EDP_BACKLIGHT_AUX_ENABLE_CAPABLE) &&
> > > + (dpcd_edp[1] &
> > DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAPABLE) &&
> > > + ((read_mode_set_reg(intel_dp) &
> > > +
> > DP_EDP_BACKLIGHT_BRIGHTNESS_CTL_MODE_DPCD_MASK))) {
> > > +
> > > + DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");
> > > +
> > > + if (dpcd_edp[1] &
> > DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
> > > + intel_dp->aux_backlight.use_lsb_reg = true;
> > > +
> > > + return true;
> > > + }
> > > + return false;
> > > +}
> > > +
> > > +#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
> > > +
> > > +/**
> > > + * Sends the current backlight level over the aux channel, checking
> > > +if its using
> > > + * 8-bit or 16 bit value (MSB and LSB) */ static void
> > > +write_aux_backlight_level(struct intel_dp *intel_dp, uint16_t level)
> > > +{
> > > + uint8_t vals[2] = { 0x0 };
> > > +
> > > + vals[0] = level;
> > > + DRM_DEBUG_KMS("Level 0x%x\n", level);
> > > +
> > > + /* Write the MSB and/or LSB */
> > > + if (intel_dp->aux_backlight.use_lsb_reg) {
> > > + vals[0] = (level & 0xFF00) >> 8;
> > > + vals[1] = (level & 0xFF);
> > > + if (drm_dp_dpcd_writeb(&intel_dp->aux,
> > > + DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
> > vals[1]) < 0) {
> > > + DRM_DEBUG_KMS("Failed to write aux backlight
> > level\n");
> > > + return;
> > > + }
> > > + }
> > > + if (drm_dp_dpcd_writeb(&intel_dp->aux,
> > DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
> > > + vals[0]) < 0) {
> > > + DRM_DEBUG_KMS("Failed to write aux backlight level\n");
> > > + return;
> > > + }
> > > + intel_dp->aux_backlight.level = level; }
> > > +
> > > +static void set_aux_backlight_enable(struct intel_dp *intel_dp, bool
> > > +enable) {
> > > + uint8_t reg_val = 0;
> > > +
> > > + if (intel_dp_dpcd_read_wake(&intel_dp->aux,
> > > + DP_EDP_DISPLAY_CONTROL_REGISTER,
> > > + &reg_val, sizeof(reg_val)) < 0) {
> > > + DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
> > > + DP_EDP_DISPLAY_CONTROL_REGISTER);
> > > + return;
> > > + }
> > > + if (enable)
> > > + reg_val |= DP_EDP_BACKLIGHT_ENABLE;
> > > + else
> > > + reg_val &= ~(DP_EDP_BACKLIGHT_ENABLE);
> > > +
> > > + if (drm_dp_dpcd_writeb(&intel_dp->aux,
> > DP_EDP_DISPLAY_CONTROL_REGISTER,
> > > + reg_val) < 0) {
> > > + DRM_DEBUG_KMS("Failed to %s aux backlight\n",
> > > + enable ? "enable" : "disable");
> > > + return;
> > > + }
> > > + intel_dp->aux_backlight.enabled = enable; }
> > > +
> > > +/**
> > > + * intel_dp_aux_backlight_device_update_status
> > > + * Writes to the sysfs backlight interface will come here to set the
> > > + * backlight level or disable/enable the backlight */ static int
> > > +intel_dp_aux_backlight_device_update_status(struct backlight_device
> > > +*bd) {
> > > + struct intel_connector *intel_connector = bl_get_data(bd);
> > > + struct drm_connector *connector = &intel_connector->base;
> > > + struct intel_encoder *intel_encoder =
> > intel_attached_encoder(connector);
> > > + struct intel_dp *intel_dp = enc_to_intel_dp(&intel_encoder->base);
> > > + struct drm_device *dev = connector->dev;
> > > + uint32_t hw_level;
> > > + bool bl_enable = false;
> > > +
> > > + DRM_DEBUG_KMS("Updating intel_aux_backlight-DP,
> > brightness=%d/%d, bl_power %d\n",
> > > + bd->props.brightness, bd->props.max_brightness,
> > > + bd->props.power);
> > > +
> > > + if (connector->status != connector_status_connected)
> > > + return -ENODEV;
> > > +
> > > + WARN_ON(intel_dp->aux_backlight.max == 0);
> > > +
> > > + drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> > > +
> > > + hw_level = scale(bd->props.brightness,
> > > + 0, bd->props.max_brightness,
> > > + intel_dp->aux_backlight.min, intel_dp-
> > >aux_backlight.max);
> > > +
> > > + if (intel_dp->aux_backlight.level != hw_level)
> > > + write_aux_backlight_level(intel_dp, hw_level);
> > > +
> > > + /*
> > > + * This gets called when bl_power is written to as well. Check if the
> > > + * bl_power state has changed and write it
> > > + */
> > > + bl_enable = (bd->props.power == FB_BLANK_UNBLANK);
> > > + if (intel_dp->aux_backlight.enabled != bl_enable)
> > > + set_aux_backlight_enable(intel_dp, bl_enable);
> > > +
> > > + drm_modeset_unlock(&dev->mode_config.connection_mutex);
> > > + return 0;
> > > +}
> > > +
> > > +/**
> > > + * intel_dp_aux_backlight_device_get_brightness
> > > + * Called on read of the sysfs backlight interface to get the current
> > > +backlight
> > > + * value from the AUX channel.
> > > + */
> > > +static int
> > > +intel_dp_aux_backlight_device_get_brightness(struct backlight_device
> > > +*bd) {
> > > + struct intel_connector *intel_connector = bl_get_data(bd);
> > > + struct drm_connector *connector = &intel_connector->base;
> > > + struct drm_device *dev = connector->dev;
> > > + struct intel_encoder *intel_encoder =
> > intel_attached_encoder(connector);
> > > + struct intel_dp *intel_dp = enc_to_intel_dp(&intel_encoder->base);
> > > + int ret;
> > > +
> > > + if (connector->status != connector_status_connected)
> > > + return -ENODEV;
> > > +
> > > + drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> > > +
> > > + intel_dp->aux_backlight.level = read_aux_backlight_level(intel_dp);
> > > +
> > > + ret = scale(intel_dp->aux_backlight.level,
> > > + intel_dp->aux_backlight.min, intel_dp-
> > >aux_backlight.max,
> > > + 0, bd->props.max_brightness);
> > > +
> > > + drm_modeset_unlock(&dev->mode_config.connection_mutex);
> > > +
> > > + return ret;
> > > +}
> > > +
> > > +const struct backlight_ops intel_dp_backlight_device_ops = {
> > > + .update_status = intel_dp_aux_backlight_device_update_status,
> > > + .get_brightness = intel_dp_aux_backlight_device_get_brightness,
> > > +};
> > > +
> > > +static void setup_backlight_ops(struct intel_backlight *backlight) {
> > > + backlight->bl_ops = &intel_dp_backlight_device_ops; } #else
> > > +
> > > +static void setup_backlight_ops(struct intel_backlight *backlight) {
> > > +
> > > +}
> > > +#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
> > > +
> > > +
> > > +static void _aux_backlight_init(struct intel_dp *intel_dp) {
> > > + struct drm_connector *connector =
> > > +&intel_dp->attached_connector->base;
> > > +
> > > + intel_dp->aux_backlight.max = MAX_AUX_BL_HW_LEVEL;
> > > + intel_dp->aux_backlight.min = MIN_AUX_BL_HW_LEVEL;
> > > +
> > > + intel_dp->aux_backlight.level = read_aux_backlight_level(intel_dp);
> > > + intel_dp->aux_backlight.enabled =
> > > +get_aux_backlight_enable(&intel_dp->aux);
> > > +
> > > + setup_backlight_ops(&intel_dp->aux_backlight);
> > > + /*
> > > + * For AUX backlight, using different name for each DP/eDP connector
> > > + * will produce registration of multiple DP-AUX backlight devices in
> > > + * the driver.
> > > + */
> > > + snprintf(intel_dp->aux_backlight.bl_name,
> > INTEL_BACKLIGHT_NAME_LEN,
> > > + "intel_aux_backlight-%s", connector->name); }
> > > +
> > > +/**
> > > + * Called on connector initialization to check for aux backlight
> > > +control
> > > + * capability and if present, initialize it.
> > > + */
> > > +
> > > +void intel_dp_aux_backlight_init(struct intel_dp *intel_dp,
> > > + struct drm_connector *connector)
> > > +{
> > > + if (!is_aux_display_control_capable(connector)) {
> > > + DRM_DEBUG_KMS("Backlight control over AUX not
> > supported\n");
> > > + return;
> > > + }
> > > + intel_dp->aux_backlight.present = true;
> > > +
> > > + _aux_backlight_init(intel_dp);
> > > +
> > > + DRM_DEBUG_KMS("Connector %s backlight %s, brightness
> > %u/%u\n",
> > > + connector->name,
> > > + intel_dp->aux_backlight.enabled ? "enabled" :
> > "disabled",
> > > + intel_dp->aux_backlight.level, intel_dp-
> > >aux_backlight.max); }
> > > +/**
> > > + * Cleanup aux backlight control data */ void
> > > +intel_dp_aux_backlight_destroy(struct drm_connector *connector) {
> > > + struct intel_encoder *intel_encoder =
> > intel_attached_encoder(connector);
> > > + struct intel_dp *intel_dp = enc_to_intel_dp(&intel_encoder->base);
> > > +
> > > + intel_dp->aux_backlight.present = false; }
> > > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > > b/drivers/gpu/drm/i915/intel_drv.h
> > > index 46484e4..438a87b 100644
> > > --- a/drivers/gpu/drm/i915/intel_drv.h
> > > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > > @@ -163,26 +163,31 @@ struct intel_encoder {
> > > enum hpd_pin hpd_pin;
> > > };
> > >
> > > +#define INTEL_BACKLIGHT_NAME_LEN 50
> > > +struct intel_backlight {
> > > + bool present;
> > > + u32 level;
> > > + u32 min;
> > > + u32 max;
> > > + bool enabled;
> > > + bool combination_mode; /* gen 2/4 only */
> > > + bool active_low_pwm;
> > > +
> > > + /* PWM chip */
> > > + struct pwm_device *pwm;
> > > +
> > > + struct backlight_device *device;
> > > + const struct backlight_ops *bl_ops;
> > > + char bl_name[INTEL_BACKLIGHT_NAME_LEN];
> > > + bool use_lsb_reg; /* aux backlight only */
> > > +};
> > > +
> > > struct intel_panel {
> > > struct drm_display_mode *fixed_mode;
> > > struct drm_display_mode *downclock_mode;
> > > int fitting_mode;
> > >
> > > - /* backlight */
> > > - struct {
> > > - bool present;
> > > - u32 level;
> > > - u32 min;
> > > - u32 max;
> > > - bool enabled;
> > > - bool combination_mode; /* gen 2/4 only */
> > > - bool active_low_pwm;
> > > -
> > > - /* PWM chip */
> > > - struct pwm_device *pwm;
> > > -
> > > - struct backlight_device *device;
> > > - } backlight;
> > > + struct intel_backlight backlight;
> > >
> > > void (*backlight_power)(struct intel_connector *, bool enable); };
> > > @@ -771,6 +776,8 @@ struct intel_dp {
> > > unsigned long compliance_test_type;
> > > unsigned long compliance_test_data;
> > > bool compliance_test_active;
> > > +
> > > + struct intel_backlight aux_backlight;
> > > };
> > >
> > > struct intel_digital_port {
> > > @@ -1210,6 +1217,11 @@ void intel_edp_drrs_invalidate(struct
> > drm_device *dev,
> > > unsigned frontbuffer_bits);
> > > void intel_edp_drrs_flush(struct drm_device *dev, unsigned
> > > frontbuffer_bits); void hsw_dp_set_ddi_pll_sel(struct
> > > intel_crtc_state *pipe_config);
> > > +bool intel_dp_get_dpcd(struct intel_dp *intel_dp); ssize_t
> > > +intel_dp_dpcd_read_wake(struct drm_dp_aux *aux, unsigned int offset,
> > > + void *buffer, size_t size);
> > > +uint32_t scale(uint32_t source_val, uint32_t source_min, uint32_t
> > source_max,
> > > + uint32_t target_min, uint32_t target_max);
> > >
> > > /* intel_dp_mst.c */
> > > int intel_dp_mst_encoder_init(struct intel_digital_port
> > > *intel_dig_port, int conn_id); @@ -1328,6 +1340,10 @@ extern struct
> > > drm_display_mode *intel_find_panel_downclock( void
> > > intel_backlight_register(struct drm_device *dev); void
> > > intel_backlight_unregister(struct drm_device *dev);
> > >
> > > +/* intel_dp_aux_backlight_ctl.c */
> > > +void intel_dp_aux_backlight_init(struct intel_dp *intel_dp,
> > > + struct drm_connector *connector);
> > > +void intel_dp_aux_backlight_destroy(struct drm_connector *connector);
> > >
> > > /* intel_psr.c */
> > > void intel_psr_enable(struct intel_dp *intel_dp); diff --git
> > > a/drivers/gpu/drm/i915/intel_panel.c
> > > b/drivers/gpu/drm/i915/intel_panel.c
> > > index 2034438a..c61fb92 100644
> > > --- a/drivers/gpu/drm/i915/intel_panel.c
> > > +++ b/drivers/gpu/drm/i915/intel_panel.c
> > > @@ -410,7 +410,7 @@ intel_panel_detect(struct drm_device *dev)
> > > * Return @source_val in range [@source_min..@source_max] scaled to
> > range
> > > * [@target_min..@target_max].
> > > */
> > > -static uint32_t scale(uint32_t source_val,
> > > +uint32_t scale(uint32_t source_val,
> > > uint32_t source_min, uint32_t source_max,
> > > uint32_t target_min, uint32_t target_max) { @@ -1151,18
> > > +1151,23 @@ static const struct backlight_ops intel_backlight_device_ops
> > = {
> > > .get_brightness = intel_backlight_device_get_brightness,
> > > };
> > >
> > > -static int intel_backlight_device_register(struct intel_connector
> > > *connector)
> > > +static void setup_backlight_ops(struct intel_backlight *backlight) {
> > > + backlight->bl_ops = &intel_backlight_device_ops; }
> > > +
> > > +static int intel_backlight_device_register(struct intel_connector
> > *connector,
> > > + struct intel_backlight *backlight)
> > > {
> > > - struct intel_panel *panel = &connector->panel;
> > > struct backlight_properties props;
> > >
> > > - if (WARN_ON(panel->backlight.device))
> > > + if (WARN_ON(backlight->device))
> > > return -ENODEV;
> > >
> > > - if (!panel->backlight.present)
> > > + if (!backlight->present)
> > > return 0;
> > >
> > > - WARN_ON(panel->backlight.max == 0);
> > > + WARN_ON(backlight->max == 0);
> > >
> > > memset(&props, 0, sizeof(props));
> > > props.type = BACKLIGHT_RAW;
> > > @@ -1171,30 +1176,25 @@ static int intel_backlight_device_register(struct
> > intel_connector *connector)
> > > * Note: Everything should work even if the backlight device max
> > > * presented to the userspace is arbitrarily chosen.
> > > */
> > > - props.max_brightness = panel->backlight.max;
> > > - props.brightness = scale_hw_to_user(connector,
> > > - panel->backlight.level,
> > > - props.max_brightness);
> > > + props.max_brightness = backlight->max;
> > > + props.brightness = scale(backlight->level, backlight->min, backlight-
> > >max,
> > > + 0, props.max_brightness);
> > >
> > > - if (panel->backlight.enabled)
> > > + if (backlight->enabled)
> > > props.power = FB_BLANK_UNBLANK;
> > > else
> > > props.power = FB_BLANK_POWERDOWN;
> > >
> > > - /*
> > > - * Note: using the same name independent of the connector
> > prevents
> > > - * registration of multiple backlight devices in the driver.
> > > - */
> > > - panel->backlight.device =
> > > - backlight_device_register("intel_backlight",
> > > + backlight->device =
> > > + backlight_device_register(backlight->bl_name,
> > > connector->base.kdev,
> > > connector,
> > > - &intel_backlight_device_ops,
> > &props);
> > > + backlight->bl_ops, &props);
> > >
> > > - if (IS_ERR(panel->backlight.device)) {
> > > + if (IS_ERR(backlight->device)) {
> > > DRM_ERROR("Failed to register backlight: %ld\n",
> > > - PTR_ERR(panel->backlight.device));
> > > - panel->backlight.device = NULL;
> > > + PTR_ERR(backlight->device));
> > > + backlight->device = NULL;
> > > return -ENODEV;
> > > }
> > >
> > > @@ -1204,21 +1204,25 @@ static int intel_backlight_device_register(struct
> > intel_connector *connector)
> > > return 0;
> > > }
> > >
> > > -static void intel_backlight_device_unregister(struct intel_connector
> > > *connector)
> > > +static void intel_backlight_device_unregister(struct intel_backlight
> > > +*backlight)
> > > {
> > > - struct intel_panel *panel = &connector->panel;
> > > -
> > > - if (panel->backlight.device) {
> > > - backlight_device_unregister(panel->backlight.device);
> > > - panel->backlight.device = NULL;
> > > + if (backlight->device) {
> > > + backlight_device_unregister(backlight->device);
> > > + backlight->device = NULL;
> > > }
> > > }
> > > +
> > > #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */ -static int
> > > intel_backlight_device_register(struct intel_connector *connector)
> > > +
> > > +static int intel_backlight_device_register(struct intel_connector
> > *connector,
> > > + struct intel_backlight *backlight)
> > > {
> > > return 0;
> > > }
> > > -static void intel_backlight_device_unregister(struct intel_connector
> > > *connector)
> > > +static void intel_backlight_device_unregister(struct intel_backlight
> > > +*backlight) { } static void setup_backlight_ops(struct
> > > +intel_backlight *backlight)
> > > {
> > > }
> > > #endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */ @@ -1652,6 +1656,17
> > @@ int
> > > intel_panel_setup_backlight(struct drm_connector *connector, enum pipe
> > > pipe)
> > >
> > > panel->backlight.present = true;
> > >
> > > + setup_backlight_ops(&panel->backlight);
> > > +
> > > + /*
> > > + * Note: For internal displays, using the same name independent of
> > the
> > > + * connector prevents registration of multiple backlight devices in the
> > > + * driver.
> > > + */
> > > + strncpy(panel->backlight.bl_name, "intel_backlight",
> > > + INTEL_BACKLIGHT_NAME_LEN);
> > > + panel->backlight.bl_name[INTEL_BACKLIGHT_NAME_LEN - 1] = '\0';
> > > +
> > > DRM_DEBUG_KMS("Connector %s backlight initialized, %s,
> > brightness %u/%u\n",
> > > connector->name,
> > > panel->backlight.enabled ? "enabled" : "disabled", @@
> > > -1757,16 +1772,42 @@ void intel_panel_fini(struct intel_panel *panel)
> > >
> > > void intel_backlight_register(struct drm_device *dev) {
> > > - struct intel_connector *connector;
> > > + struct intel_connector *intel_connector;
> > > +
> > > + list_for_each_entry(intel_connector, &dev-
> > >mode_config.connector_list,
> > > + base.head) {
> > > + struct drm_connector *connector = &intel_connector->base;
> > > +
> > > + intel_backlight_device_register(intel_connector,
> > > + &intel_connector->panel.backlight);
> > > +
> > > + if (connector->connector_type ==
> > DRM_MODE_CONNECTOR_DisplayPort ||
> > > + connector->connector_type ==
> > DRM_MODE_CONNECTOR_eDP) {
> > > + struct intel_encoder *encoder =
> > intel_attached_encoder(connector);
> > > + struct intel_dp *intel_dp =
> > enc_to_intel_dp(&encoder->base);
> > >
> > > - list_for_each_entry(connector, &dev->mode_config.connector_list,
> > base.head)
> > > - intel_backlight_device_register(connector);
> > > + intel_backlight_device_register(intel_connector,
> > > + &intel_dp->aux_backlight);
> > > + }
> > > + }
> > > }
> > >
> > > void intel_backlight_unregister(struct drm_device *dev) {
> > > - struct intel_connector *connector;
> > > + struct intel_connector *intel_connector;
> > > +
> > > + list_for_each_entry(intel_connector, &dev-
> > >mode_config.connector_list,
> > > + base.head) {
> > > + struct drm_connector *connector = &intel_connector->base;
> > > +
> > > +
> > > +intel_backlight_device_unregister(&intel_connector->panel.backlight);
> > >
> > > - list_for_each_entry(connector, &dev->mode_config.connector_list,
> > base.head)
> > > - intel_backlight_device_unregister(connector);
> > > + if (connector->connector_type ==
> > DRM_MODE_CONNECTOR_DisplayPort ||
> > > + connector->connector_type ==
> > DRM_MODE_CONNECTOR_eDP) {
> > > + struct intel_encoder *encoder =
> > intel_attached_encoder(connector);
> > > + struct intel_dp *intel_dp =
> > enc_to_intel_dp(&encoder->base);
> > > +
> > > + intel_backlight_device_unregister(&intel_dp-
> > >aux_backlight);
> > > + }
> > > + }
> > > }
> > > diff --git a/include/drm/drm_dp_helper.h
> > b/include/drm/drm_dp_helper.h
> > > index 8c52d0ef1..5826183 100644
> > > --- a/include/drm/drm_dp_helper.h
> > > +++ b/include/drm/drm_dp_helper.h
> > > @@ -455,16 +455,22 @@
> > > # define DP_EDP_14 0x03
> > >
> > > #define DP_EDP_GENERAL_CAP_1 0x701
> > > +#define DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAPABLE (1 << 0)
> > > +#define DP_EDP_BACKLIGHT_AUX_ENABLE_CAPABLE (1 << 2)
> > >
> > > #define DP_EDP_BACKLIGHT_ADJUSTMENT_CAP 0x702
> > > +#define DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAPABLE (1 << 1)
> > > +#define DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT (1 << 2)
> > >
> > > #define DP_EDP_GENERAL_CAP_2 0x703
> > >
> > > #define DP_EDP_GENERAL_CAP_3 0x704 /* eDP 1.4 */
> > >
> > > #define DP_EDP_DISPLAY_CONTROL_REGISTER 0x720
> > > +#define DP_EDP_BACKLIGHT_ENABLE (1 << 0)
> > >
> > > #define DP_EDP_BACKLIGHT_MODE_SET_REGISTER 0x721
> > > +#define DP_EDP_BACKLIGHT_BRIGHTNESS_CTL_MODE_DPCD_MASK 0x2
> > >
> > > #define DP_EDP_BACKLIGHT_BRIGHTNESS_MSB 0x722
> > > #define DP_EDP_BACKLIGHT_BRIGHTNESS_LSB 0x723
> > > --
> > > 1.9.3
> > >
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch

--
Daniel Vetter
Software Engineer, Intel Corporation