[Intel-gfx] [PATCH 3/3] drm/i915: CABC support for backlight control
Jani Nikula
jani.nikula at intel.com
Thu Mar 24 14:55:47 UTC 2016
On Thu, 24 Mar 2016, Deepak M <m.deepak at intel.com> wrote:
> In CABC (Content Adaptive Brightness Control) content grey level
> scale can be increased while simultaneously decreasing
> brightness of the backlight to achieve same perceived brightness.
>
> The CABC is not standardized and panel vendors are free to follow
> their implementation. The CABC implementaion here assumes that the
> panels use standard SW register for control.
>
> In this design there will be no PWM signal from the SoC and DCS
> commands are sent to enable and control the backlight brightness.
>
> v2: Moving the CABC bkl functions to new file.(Jani)
>
> v3: Rebase
>
> v4: Rebase
>
> v5: Use mipi_dsi_dcs_write() instead of mipi_dsi_dcs_write_buffer() (Jani)
> Move DCS macro`s to include/video/mipi_display.h (Jani)
>
> Cc: Jani Nikula <jani.nikula at intel.com>
> Cc: Daniel Vetter <daniel.vetter at intel.com>
> Cc: Yetunde Adebisi <yetundex.adebisi at intel.com>
> Signed-off-by: Deepak M <m.deepak at intel.com>
> ---
> drivers/gpu/drm/i915/Makefile | 1 +
> drivers/gpu/drm/i915/i915_drv.h | 1 -
> drivers/gpu/drm/i915/intel_drv.h | 2 +
> drivers/gpu/drm/i915/intel_dsi.c | 19 ++++-
> drivers/gpu/drm/i915/intel_dsi.h | 4 +
> drivers/gpu/drm/i915/intel_dsi_cabc.c | 154 ++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/intel_panel.c | 4 +
> 7 files changed, 182 insertions(+), 3 deletions(-)
> create mode 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 7ffb51b..065c410 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -83,6 +83,7 @@ i915-y += dvo_ch7017.o \
> intel_dp_mst.o \
> intel_dp.o \
> intel_dsi.o \
> + intel_dsi_cabc.o \
> intel_dsi_panel_vbt.o \
> intel_dsi_pll.o \
> intel_dvo.o \
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 050d860..9ed60f8 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -3489,7 +3489,6 @@ void intel_sbi_write(struct drm_i915_private *dev_priv, u16 reg, u32 value,
> enum intel_sbi_destination destination);
> u32 vlv_flisdsi_read(struct drm_i915_private *dev_priv, u32 reg);
> void vlv_flisdsi_write(struct drm_i915_private *dev_priv, u32 reg, u32 val);
> -
Superfluous whitepace change.
> int intel_gpu_freq(struct drm_i915_private *dev_priv, int val);
> int intel_freq_opcode(struct drm_i915_private *dev_priv, int val);
>
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index c87b450..9e49396 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1325,6 +1325,8 @@ void intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port);
> /* intel_dsi.c */
> void intel_dsi_init(struct drm_device *dev);
>
> +/* intel_dsi_cabc.c */
> +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector *intel_connector);
>
> /* intel_dvo.c */
> void intel_dvo_init(struct drm_device *dev);
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 456676c..7aa707f 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -1209,10 +1209,25 @@ void intel_dsi_init(struct drm_device *dev)
> else
> intel_encoder->crtc_mask = BIT(PIPE_B);
>
> - if (dev_priv->vbt.dsi.config->dual_link)
> + if (dev_priv->vbt.dsi.config->dual_link) {
> intel_dsi->ports = BIT(PORT_A) | BIT(PORT_C);
> - else
> + switch (dev_priv->vbt.dsi.config->dl_cabc_port) {
> + case CABC_PORT_A:
> + intel_dsi->bkl_dcs_ports = BIT(PORT_A);
> + break;
> + case CABC_PORT_C:
> + intel_dsi->bkl_dcs_ports = BIT(PORT_C);
> + break;
> + case CABC_PORT_A_AND_C:
> + intel_dsi->bkl_dcs_ports = BIT(PORT_A) | BIT(PORT_C);
> + break;
> + default:
> + DRM_ERROR("Unknown MIPI ports for sending DCS\n");
Is it a good idea to leave the field uninitialized in this case? Maybe
go for both ports?
> + }
> + } else {
> intel_dsi->ports = BIT(port);
> + intel_dsi->bkl_dcs_ports = BIT(port);
> + }
>
> /* Create a DSI host (and a device) for each port. */
> for_each_dsi_port(port, intel_dsi->ports) {
> diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
> index 0e758f1..5c07d59 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.h
> +++ b/drivers/gpu/drm/i915/intel_dsi.h
> @@ -34,6 +34,10 @@
> #define DSI_DUAL_LINK_FRONT_BACK 1
> #define DSI_DUAL_LINK_PIXEL_ALT 2
>
> +#define CABC_PORT_A 0x00
> +#define CABC_PORT_C 0x01
> +#define CABC_PORT_A_AND_C 0x02
> +
> struct intel_dsi_host;
>
> struct intel_dsi {
> diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.c b/drivers/gpu/drm/i915/intel_dsi_cabc.c
> new file mode 100644
> index 0000000..230ee4f
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_dsi_cabc.c
> @@ -0,0 +1,154 @@
> +/*
> + * Copyright © 2016 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.
> + *
> + * Author: Deepak M <m.deepak at intel.com>
> + */
> +
> +#include "intel_drv.h"
> +#include "intel_dsi.h"
> +#include "i915_drv.h"
> +#include <video/mipi_display.h>
> +#include <drm/drm_mipi_dsi.h>
> +
> +#define CABC_OFF (0 << 0)
> +#define CABC_USER_INTERFACE_IMAGE (1 << 0)
> +#define CABC_STILL_PICTURE (2 << 0)
> +#define CABC_VIDEO_MODE (3 << 0)
> +
> +#define CABC_BACKLIGHT (1 << 2)
> +#define CABC_DIMMING_DISPLAY (1 << 3)
> +#define CABC_BCTRL (1 << 5)
> +
> +#define CABC_MAX_VALUE 0xFF
> +
> +static u32 cabc_get_backlight(struct intel_connector *connector)
> +{
> + struct intel_encoder *encoder = connector->encoder;
> + struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> + struct mipi_dsi_device *dsi_device;
> + u8 data[2] = {0};
> + enum port port;
> +
> + for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
So, it seems weird to do the brightness read on both ports, and
overwrite the result on the second round. Do you have any further info
on this?
VBT only refers to "Panel PWM Bklt Controller On/OFF commands" and "CABC
On/OFF commands". I don't know what should be done with brightness
commands in dual link case.
> + dsi_device = intel_dsi->dsi_hosts[port]->device;
> + mipi_dsi_dcs_read(dsi_device, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
> + data, 2);
> + }
> +
> + return data[1];
So the spec says,
"Only one parameter is returned for devices that support 8-bit
brightness levels. Two parameters are returned for devices that support
between 9-bit and 16-bit brightness levels."
That's an annoying spec, but your implementation seems wrong for both
8-bit and 16-bit brightness. With the former, you'll only get one byte,
and you'll return the 0-initialized second byte. With the latter, you'll
get two bytes, but you'll return the least significant byte.
If, for starters, we assume 8-bit brightness, I think you should just
read one byte. (Given the spec, and depending on the hw implementation,
this might just work for 16-bit panes as well by way of reading/writing
the MSB.)
> +}
> +
> +static void cabc_set_backlight(struct intel_connector *connector, u32 level)
> +{
> + struct intel_encoder *encoder = connector->encoder;
> + struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> + struct mipi_dsi_device *dsi_device;
> + u8 data = 0;
No need to initialize this.
> + enum port port;
> +
> + for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
> + dsi_device = intel_dsi->dsi_hosts[port]->device;
> + data = level;
> + mipi_dsi_dcs_write(dsi_device, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
> + &data, sizeof(data));
> + }
This seems right for 8-bit brightness.
I'm still clueless which ports this command should be sent to though.
> +}
> +
> +static void cabc_disable_backlight(struct intel_connector *connector)
> +{
> + struct intel_encoder *encoder = connector->encoder;
> + struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> + struct mipi_dsi_device *dsi_device;
> + enum port port;
> + u8 data = 0;
No need to initialize this.
> +
> + cabc_set_backlight(connector, 0);
> +
> + for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
> + dsi_device = intel_dsi->dsi_hosts[port]->device;
> + data = CABC_OFF;
> + mipi_dsi_dcs_write(dsi_device, MIPI_DCS_WRITE_POWER_SAVE,
> + &data, sizeof(data));
> + mipi_dsi_dcs_write(dsi_device, MIPI_DCS_WRITE_CONTROL_DISPLAY,
> + &data, sizeof(data));
Here, it seems to me MIPI_DCS_WRITE_POWER_SAVE is a "CABC On/OFF
command" while MIPI_DCS_WRITE_CONTROL_DISPLAY is a "Panel PWM Bklt
Controller On/OFF command", but I'm just guessing.
> + }
> +}
> +
> +static void cabc_enable_backlight(struct intel_connector *connector)
> +{
> + struct intel_encoder *encoder = connector->encoder;
> + struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> + struct intel_panel *panel = &connector->panel;
> + struct mipi_dsi_device *dsi_device;
> + enum port port;
> + u8 data = 0;
No need to initialize this.
> +
> + for_each_dsi_port(port, intel_dsi->bkl_dcs_ports) {
> + dsi_device = intel_dsi->dsi_hosts[port]->device;
> + data = CABC_BACKLIGHT | CABC_DIMMING_DISPLAY | CABC_BCTRL;
> + mipi_dsi_dcs_write(dsi_device, MIPI_DCS_WRITE_CONTROL_DISPLAY,
> + &data, sizeof(data));
> + data = CABC_STILL_PICTURE;
> + mipi_dsi_dcs_write(dsi_device, MIPI_DCS_WRITE_POWER_SAVE,
> + &data, sizeof(data));
Same here as above wrt ports.
> + }
> +
> + cabc_set_backlight(connector, panel->backlight.level);
> +}
> +
> +static int cabc_setup_backlight(struct intel_connector *connector,
> + enum pipe unused)
> +{
> + struct intel_panel *panel = &connector->panel;
> +
> + panel->backlight.max = CABC_MAX_VALUE;
> + panel->backlight.level = CABC_MAX_VALUE;
> +
> + return 0;
> +}
> +
> +int intel_dsi_cabc_init_backlight_funcs(struct intel_connector *intel_connector)
> +{
> + struct drm_device *dev = intel_connector->base.dev;
> + struct drm_i915_private *dev_priv = dev->dev_private;
> + struct intel_encoder *encoder = intel_connector->encoder;
> + struct intel_panel *panel = &intel_connector->panel;
> +
> + if (!dev_priv->vbt.dsi.config->cabc_supported)
> + return -ENODEV;
> +
> + if (encoder->type != INTEL_OUTPUT_DSI) {
> + DRM_ERROR("Use DSI encoder for CABC\n");
> + return -EINVAL;
> + }
> +
> + if (WARN_ON(encoder->type != INTEL_OUTPUT_DSI))
> + return -EINVAL;
I meant you should add this *instead* of the one above. They do have the
same condition and all...
> +
> + panel->backlight.setup = cabc_setup_backlight;
> + panel->backlight.enable = cabc_enable_backlight;
> + panel->backlight.disable = cabc_disable_backlight;
> + panel->backlight.set = cabc_set_backlight;
> + panel->backlight.get = cabc_get_backlight;
> +
> + return 0;
> +}
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index 8c8996f..641c38f 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -1718,6 +1718,10 @@ 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_DSI &&
> + intel_dsi_cabc_init_backlight_funcs(connector) == 0)
> + return;
> +
> if (IS_BROXTON(dev_priv)) {
> panel->backlight.setup = bxt_setup_backlight;
> panel->backlight.enable = bxt_enable_backlight;
--
Jani Nikula, Intel Open Source Technology Center
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