Disable ABM feature when the system is running on AC mode to get
the more perfect contrast of the display.

Signed-off-by: Ryan Lin <tsung-hua.lin@amd.com>

---
 drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c      |  4 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c    |  1 +
 drivers/gpu/drm/amd/display/dc/dce/dmub_abm.c | 58 ++++++++++++-------
 drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h       |  1 +
 4 files changed, 42 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
index c560c1ab62ecb..bc8bb9aad2e36 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
@@ -822,6 +822,10 @@ static int amdgpu_acpi_event(struct notifier_block *nb,
        struct amdgpu_device *adev = container_of(nb, struct amdgpu_device, acpi_nb);
        struct acpi_bus_event *entry = (struct acpi_bus_event *)data;

+       if (strcmp(entry->device_class, "battery") == 0) {
+               adev->pm.ac_power = power_supply_is_system_supplied() > 0;
+       }
+
        if (strcmp(entry->device_class, ACPI_AC_CLASS) == 0) {
                if (power_supply_is_system_supplied() > 0)
                        DRM_DEBUG_DRIVER("pm: AC\n");
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index abfcc1304ba0c..3a0afe7602727 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3454,6 +3454,7 @@ int amdgpu_device_init(struct amdgpu_device *adev,

        adev->gfx.gfx_off_req_count = 1;
        adev->pm.ac_power = power_supply_is_system_supplied() > 0;
+       adev->pm.old_ac_power = true;

        atomic_set(&adev->throttling_logging_enabled, 1);
        /*
diff --git a/drivers/gpu/drm/amd/display/dc/dce/dmub_abm.c b/drivers/gpu/drm/amd/display/dc/dce/dmub_abm.c
index 54a1408c8015c..478a734b66926 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dmub_abm.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dmub_abm.c
@@ -23,6 +23,8 @@
  *
  */

+#include <linux/power_supply.h>
+#include "amdgpu.h"
 #include "dmub_abm.h"
 #include "dce_abm.h"
 #include "dc.h"
@@ -51,6 +53,7 @@
 #define DISABLE_ABM_IMMEDIATELY 255


+extern uint amdgpu_dm_abm_level;

 static void dmub_abm_enable_fractional_pwm(struct dc_context *dc)
 {
@@ -117,28 +120,6 @@ static void dmub_abm_init(struct abm *abm, uint32_t backlight)
        dmub_abm_enable_fractional_pwm(abm->ctx);
 }

-static unsigned int dmub_abm_get_current_backlight(struct abm *abm)
-{
-       struct dce_abm *dce_abm = TO_DMUB_ABM(abm);
-       unsigned int backlight = REG_READ(BL1_PWM_CURRENT_ABM_LEVEL);
-
-       /* return backlight in hardware format which is unsigned 17 bits, with
-        * 1 bit integer and 16 bit fractional
-        */
-       return backlight;
-}
-
-static unsigned int dmub_abm_get_target_backlight(struct abm *abm)
-{
-       struct dce_abm *dce_abm = TO_DMUB_ABM(abm);
-       unsigned int backlight = REG_READ(BL1_PWM_TARGET_ABM_LEVEL);
-
-       /* return backlight in hardware format which is unsigned 17 bits, with
-        * 1 bit integer and 16 bit fractional
-        */
-       return backlight;
-}
-
 static bool dmub_abm_set_level(struct abm *abm, uint32_t level)
 {
        union dmub_rb_cmd cmd;
@@ -148,6 +129,9 @@ static bool dmub_abm_set_level(struct abm *abm, uint32_t level)
        int edp_num;
        uint8_t panel_mask = 0;

+       if (power_supply_is_system_supplied() > 0)
+               level = 0;
+
        get_edp_links(dc->dc, edp_links, &edp_num);

        for (i = 0; i < edp_num; i++) {
@@ -170,6 +154,36 @@ static bool dmub_abm_set_level(struct abm *abm, uint32_t level)
        return true;
 }

+static unsigned int dmub_abm_get_current_backlight(struct abm *abm)
+{
+       struct dce_abm *dce_abm = TO_DMUB_ABM(abm);
+       unsigned int backlight = REG_READ(BL1_PWM_CURRENT_ABM_LEVEL);
+       struct dc_context *dc = abm->ctx;
+       struct amdgpu_device *adev = dc->driver_context;
+
+       if (adev->pm.ac_power != adev->pm.old_ac_power) {
+               dmub_abm_set_level(abm, amdgpu_dm_abm_level);
+               adev->pm.ac_power = power_supply_is_system_supplied() > 0;
+               adev->pm.old_ac_power = adev->pm.ac_power;
+       }
+
+       /* return backlight in hardware format which is unsigned 17 bits, with
+        * 1 bit integer and 16 bit fractional
+        */
+       return backlight;
+}
+
+static unsigned int dmub_abm_get_target_backlight(struct abm *abm)
+{
+       struct dce_abm *dce_abm = TO_DMUB_ABM(abm);
+       unsigned int backlight = REG_READ(BL1_PWM_TARGET_ABM_LEVEL);
+
+       /* return backlight in hardware format which is unsigned 17 bits, with
+        * 1 bit integer and 16 bit fractional
+        */
+       return backlight;
+}
+
 static bool dmub_abm_init_config(struct abm *abm,
        const char *src,
        unsigned int bytes,
diff --git a/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h b/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h
index f6e0e7d8a0077..de459411a0e83 100644
--- a/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h
+++ b/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h
@@ -445,6 +445,7 @@ struct amdgpu_pm {
        uint32_t                smu_prv_buffer_size;
        struct amdgpu_bo        *smu_prv_buffer;
        bool ac_power;
+       bool old_ac_power;
        /* powerplay feature */
        uint32_t pp_feature;

--
2.25.1