[Intel-gfx] [PATCH 2/2] drm/i915: Add Backlight Control using DPCD for eDP connectors (v6)
Thulasimani, Sivakumar
sivakumar.thulasimani at intel.com
Tue Feb 9 13:29:05 UTC 2016
On 2/9/2016 6:41 PM, Adebisi, YetundeX wrote:
>
>> -----Original Message-----
>> From: Thulasimani, Sivakumar
>> Sent: Monday, February 08, 2016 8:57 AM
>> To: Adebisi, YetundeX; intel-gfx at lists.freedesktop.org
>> Cc: Nikula, Jani
>> Subject: Re: [Intel-gfx] [PATCH 2/2] drm/i915: Add Backlight Control using
>> DPCD for eDP connectors (v6)
>>
>>
>>
>> On 2/5/2016 5:48 PM, Yetunde Adebisi 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
>>>
>>> v4: Updated to use AUX backlight control if PWM control is not possible
>>> (Jani)
>>> v5: Moved call to initialize backlight registers to
>>> dp_aux_setup_backlight
>>> v6: Check DP_EDP_BACKLIGHT_PIN_ENABLE_CAP is disabled before
>> setting
>>> up AUX backlight control. To fix BLM_PWM_ENABLE igt test warnings on
>>> bdw_ultra
>>>
>>> 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 | 17 ++-
>>> drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 170
>> ++++++++++++++++++++++++++
>>> drivers/gpu/drm/i915/intel_drv.h | 6 +
>>> drivers/gpu/drm/i915/intel_panel.c | 4 +
>>> 5 files changed, 192 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..41250cc 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 \
>>> 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 a073f04..9f8672e 100644
>>> --- a/drivers/gpu/drm/i915/intel_dp.c
>>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>>> @@ -3183,7 +3183,7 @@ 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)
>>> {
>>> @@ -3850,7 +3850,6 @@ 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) @@ -3886,6
>> +3885,15 @@
>>> 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 */
>>> + memset(intel_dp->edp_dpcd, 0, sizeof(intel_dp-
>>> edp_dpcd));
>>> + 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->edp_dpcd,
>> sizeof(intel_dp->edp_dpcd)) ==
>>> +
>> sizeof(intel_dp->edp_dpcd)))
>>> + DRM_DEBUG_KMS("EDP DPCD : %*ph\n", (int)
>> sizeof(intel_dp->edp_dpcd),
>>> + intel_dp->edp_dpcd);
>>> }
>>>
>>> DRM_DEBUG_KMS("Display Port TPS3 support: source %s, sink
>> %s\n", @@
>>> -3893,10 +3901,7 @@ 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->edp_dpcd[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..a5361d6
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
>>> @@ -0,0 +1,170 @@
>>> +/*
>>> + * 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 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->edp_dpcd[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 };
>>> +
>>> + vals[0] = level;
>>> +
>>> + /* Write the MSB and/or LSB */
>>> + if (intel_dp->edp_dpcd[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) {
>>> + struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder-
>>> base);
>>> + uint8_t dpcd_buf = 0;
>>> +
>>> + set_aux_backlight_enable(intel_dp, true);
>>> +
>>> + if ((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_PRESET))
>>> + drm_dp_dpcd_writeb(&intel_dp->aux,
>> DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
>>> + (dpcd_buf |
>> DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD));
>>> +}
>>> +
>>> +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;
>>> +
>>> + intel_dp_aux_enable_backlight(connector);
>>> +
>>> + if (intel_dp->edp_dpcd[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 = panel->backlight.level != 0;
>>> +
>>> + 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);
>>> +
>>> + /* Check the eDP Display control capabilities registers to determine if
>>> + * the panel can support backlight control over the aux channel
>>> + */
>>> + if (intel_dp->edp_dpcd[1] &
>> DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
>>> + (intel_dp->edp_dpcd[1] &
>> DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
>>> + !((intel_dp->edp_dpcd[1] &
>> DP_EDP_BACKLIGHT_PIN_ENABLE_CAP) ||
>>> + (intel_dp->edp_dpcd[2] &
>>> +DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))) {
>>> +
>>> + 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 93ba14a..e19ee22 100644
>>> --- a/drivers/gpu/drm/i915/intel_drv.h
>>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>>> @@ -761,6 +761,7 @@ 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 edp_dpcd[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];
>>> @@ -1287,6 +1288,11 @@ 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 21ee647..941c6fe 100644
>>> --- a/drivers/gpu/drm/i915/intel_panel.c
>>> +++ b/drivers/gpu/drm/i915/intel_panel.c
>>> @@ -1720,6 +1720,10 @@ intel_panel_init_backlight_funcs(struct
>> intel_panel *panel)
>>> container_of(panel, struct intel_connector, panel);
>>> struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>>>
>>> + if (connector->base.connector_type ==
>> DRM_MODE_CONNECTOR_eDP &&
>>> + intel_dp_aux_init_backlight_funcs(connector) == 0)
>>> + return;
>>> +
>> can we make this feature to be enabled explicitly rather than if the panel
>> supports it ? we have never checked for these dpcd registers till now and it is
>> quite possible for any one panel to pass this even though we are using it with
>> PWM based control at present. i.e we keep PSR disabled still since it is not
>> working always, why should we enable this by default :).
> I can do that if there is no objection. Something like enable_dcpd_backlight parameter?
yes,that should make this better. anything that can avoid a regression
is good :).
>> i understand i am late to this thread, but good to check late at-least.
>> did you test with DPST disabled or does this affect the panel usability with
>> dpst enabled or disabled ?
>> Sivakumar
> I have not tested it with DPST, how do I enable DPST?
DPST should be on by default. in case you have not observed any
flickering or brightness changes during various contents then
it should be fine.
Sivakumar
>>> if (IS_BROXTON(dev_priv)) {
>>> panel->backlight.setup = bxt_setup_backlight;
>>> panel->backlight.enable = bxt_enable_backlight;
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