[Intel-gfx] [PATCH] drm/i915: Add Backlight Control using DPCD for eDP connectors (v3)
Jani Nikula
jani.nikula at intel.com
Fri Nov 20 07:04:12 PST 2015
On Mon, 16 Nov 2015, Yetunde Adebisi <yetundex.adebisi at intel.com> wrote:
> This patch adds support for eDP backlight control using DPCD registers to
> backlight hooks in intel_panel.
>
> It checks for backlight control over AUX channel capability and sets up
> function pointers to get and set the backlight brightness level if
> supported.
>
> v2: Moved backlight functions from intel_dp.c into a new file
> intel_dp_aux_backlight.c. Also moved reading of eDP display control
> registers to intel_dp_get_dpcd
>
> v3: Correct some formatting mistakes
>
> This patch depends on http://patchwork.freedesktop.org/patch/64253/
>
> Cc: Bob Paauwe <bob.j.paauwe at intel.com>
> Cc: Jani Nikula <jani.nikula at intel.com>
> Acked-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> Signed-off-by: Yetunde Adebisi <yetundex.adebisi at intel.com>
> ---
> drivers/gpu/drm/i915/Makefile | 1 +
> drivers/gpu/drm/i915/intel_dp.c | 16 ++-
> drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 177 ++++++++++++++++++++++++++
> drivers/gpu/drm/i915/intel_drv.h | 6 +
> drivers/gpu/drm/i915/intel_panel.c | 4 +
> 5 files changed, 198 insertions(+), 6 deletions(-)
> create mode 100644 drivers/gpu/drm/i915/intel_dp_aux_backlight.c
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 0851de07..7a1db3d 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.o\
Space before \ please.
> intel_dp_link_training.o \
> intel_dp_mst.o \
> intel_dp.o \
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 8071247..22e0241 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3156,7 +3156,7 @@ 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)
> {
> @@ -3823,7 +3823,6 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> struct drm_device *dev = dig_port->base.base.dev;
> struct drm_i915_private *dev_priv = dev->dev_private;
> - uint8_t rev;
>
> if (intel_dp_dpcd_read_wake(&intel_dp->aux, 0x000, intel_dp->dpcd,
> sizeof(intel_dp->dpcd)) < 0)
> @@ -3859,6 +3858,14 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> DRM_DEBUG_KMS("PSR2 %s on sink",
> dev_priv->psr.psr2_support ? "supported" : "not supported");
> }
> +
> + /* Read the eDP Display control capabilities registers */
You need to clear intel_dp->dpcd_edp here.
> + if ((intel_dp->dpcd[DP_EDP_CONFIGURATION_CAP] & DP_DPCD_DISPLAY_CONTROL_CAPABLE) &&
> + (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_EDP_DPCD_REV,
> + intel_dp->dpcd_edp, sizeof(intel_dp->dpcd_edp)) ==
> + sizeof(intel_dp->dpcd_edp)))
> + DRM_DEBUG_KMS("EDP DPCD : %*ph\n", (int) sizeof(intel_dp->dpcd_edp),
> + intel_dp->dpcd_edp);
> }
>
> DRM_DEBUG_KMS("Display Port TPS3 support: source %s, sink %s\n",
> @@ -3866,10 +3873,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> yesno(drm_dp_tps3_supported(intel_dp->dpcd)));
>
> /* Intermediate frequency support */
> - if (is_edp(intel_dp) &&
> - (intel_dp->dpcd[DP_EDP_CONFIGURATION_CAP] & DP_DPCD_DISPLAY_CONTROL_CAPABLE) &&
> - (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_EDP_DPCD_REV, &rev, 1) == 1) &&
> - (rev >= 0x03)) { /* eDp v1.4 or higher */
> + if (is_edp(intel_dp) && (intel_dp->dpcd_edp[0] >= 0x03)) { /* eDp v1.4 or higher */
> __le16 sink_rates[DP_MAX_SUPPORTED_RATES];
> int i;
>
> diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> new file mode 100644
> index 0000000..190c5d9
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> @@ -0,0 +1,177 @@
> +/*
> + * 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"
> +
> +static bool is_aux_backlight_enabled(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 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,
> + ®_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");
> + }
> +}
> +
> +/*
> + * 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 uint32_t intel_dp_aux_get_backlight(struct intel_connector *connector)
> +{
> + struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
> + uint8_t read_val[2] = { 0x0 };
> + uint16_t level = 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;
> + }
> + level = read_val[0];
> + if (intel_dp->dpcd_edp[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
> + level = (read_val[0] << 8 | read_val[1]);
> +
> + return level;
> +}
> +
> +/*
> + * Sends the current backlight level over the aux channel, checking if its using
> + * 8-bit or 16 bit value (MSB and LSB)
> + */
> +static void
> +intel_dp_aux_set_backlight(struct intel_connector *connector, u32 level)
> +{
> + struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
> + uint8_t vals[2] = { 0x0 };
> +
> + DRM_DEBUG_KMS("Level 0x%x\n", level);
The caller of the hook does debug logging already.
> + vals[0] = level;
> +
> + /* Write the MSB and/or LSB */
> + if (intel_dp->dpcd_edp[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT) {
> + vals[0] = (level & 0xFF00) >> 8;
> + vals[1] = (level & 0xFF);
> + }
> + if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
> + vals, sizeof(vals)) < 0) {
> + DRM_DEBUG_KMS("Failed to write aux backlight level\n");
> + return;
> + }
> +}
> +
> +static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
> +{
> + set_aux_backlight_enable(enc_to_intel_dp(&connector->encoder->base), true);
> +}
> +
> +static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
> +{
> + set_aux_backlight_enable(enc_to_intel_dp(&connector->encoder->base), false);
> +}
> +
> +static int intel_dp_aux_setup_backlight(struct intel_connector *connector,
> + enum pipe pipe)
> +{
> + struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
> + struct intel_panel *panel = &connector->panel;
> +
> + if (intel_dp->dpcd_edp[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
> + panel->backlight.max = 0xFFFF;
> + else
> + panel->backlight.max = 0xFF;
> +
> + panel->backlight.min = 0;
> +
> + panel->backlight.level = intel_dp_aux_get_backlight(connector);
> + panel->backlight.enabled = is_aux_backlight_enabled(&intel_dp->aux);
> +
> + return 0;
> +}
> +
> +static bool intel_dp_aux_display_control_capable(struct intel_connector *connector)
> +{
> + struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
> + uint8_t dpcd_buf = 0;
> +
> + /* Check the eDP Display control capabilities registers to determine if
> + * the panel can support backlight control over the aux channel*/
> +
> + if (intel_dp->dpcd_edp[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
> + (intel_dp->dpcd_edp[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
> + (intel_dp->dpcd_edp[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) &&
> + ((intel_dp_dpcd_read_wake(&intel_dp->aux,
> + DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf, 1) == 1) &&
> + ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) ==
> + DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD))) {
The DP_EDP_BACKLIGHT_MODE_SET_REGISTER is a read/write register for
configuration. You can also *set* the control method. Apparently this
now trusts the BIOS to have written the right value here. I am not sure
this is the right way to go.
How about checking that aux control is possible *and* pwm control is not
possible, and then setting the mode accordingly?
Also, the power-on default for the mode is
DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET, which means a power cycle will fix
the brightness to a preset level and the brightness adjustment will
cease to work. Did you test this? I think you should write the mode in
backlight enable.
> +
> + DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");
> +
> + return true;
> + }
> + return false;
> +}
> +
> +int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector)
> +{
> + struct intel_panel *panel = &intel_connector->panel;
> +
> + if (!intel_dp_aux_display_control_capable(intel_connector))
> + return -ENODEV;
> +
> + panel->backlight.setup = intel_dp_aux_setup_backlight;
> + panel->backlight.enable = intel_dp_aux_enable_backlight;
> + panel->backlight.disable = intel_dp_aux_disable_backlight;
> + panel->backlight.set = intel_dp_aux_set_backlight;
> + panel->backlight.get = intel_dp_aux_get_backlight;
> +
> + return 0;
> +}
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index ad17288..095df8d 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -758,6 +758,7 @@ struct intel_dp {
> uint8_t dpcd[DP_RECEIVER_CAP_SIZE];
> uint8_t psr_dpcd[EDP_PSR_RECEIVER_CAP_SIZE];
> uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
> + uint8_t dpcd_edp[EDP_DISPLAY_CTL_CAP_SIZE];
> /* sink rates as reported by DP_SUPPORTED_LINK_RATES */
> uint8_t num_sink_rates;
> int sink_rates[DP_MAX_SUPPORTED_RATES];
> @@ -1279,6 +1280,11 @@ void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
> bool intel_dp_source_supports_hbr2(struct intel_dp *intel_dp);
> bool
> intel_dp_get_link_status(struct intel_dp *intel_dp, uint8_t link_status[DP_LINK_STATUS_SIZE]);
> +ssize_t intel_dp_dpcd_read_wake(struct drm_dp_aux *aux, unsigned int offset,
> + void *buffer, size_t size);
> +
> +/* intel_dp_aux_backlight.c */
> +int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
>
> /* intel_dp_mst.c */
> int intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_id);
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index a24df35..7da49b5 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -1744,6 +1744,10 @@ intel_panel_init_backlight_funcs(struct intel_panel *panel)
> struct drm_device *dev = intel_connector->base.dev;
> struct drm_i915_private *dev_priv = dev->dev_private;
>
> + if (intel_connector->base.connector_type == DRM_MODE_CONNECTOR_eDP &&
> + intel_dp_aux_init_backlight_funcs(intel_connector) == 0)
> + return;
> +
> if (IS_BROXTON(dev)) {
> panel->backlight.setup = bxt_setup_backlight;
> panel->backlight.enable = bxt_enable_backlight;
--
Jani Nikula, Intel Open Source Technology Center
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