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

Daniel Vetter
2015-09-10T15:18:18Z

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.

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 © 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