[PATCH v2 3/25] drm/amdgpu: Disable ABM when AC mode

Lin, Tsung-hua (Ryan) Tsung-hua.Lin at amd.com
Fri Mar 25 07:09:58 UTC 2022


[AMD Official Use Only]

Hi Christian,

There is already a string comparison in the same function. I just reference that to port this solution.



#define ACPI_AC_CLASS           "ac_adapter"


static int amdgpu_acpi_event(struct notifier_block *nb,
			     unsigned long val,
			     void *data)
{
	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) {      <-------------------here!
		if (power_supply_is_system_supplied() > 0)
			DRM_DEBUG_DRIVER("pm: AC\n");
		else
			DRM_DEBUG_DRIVER("pm: DC\n");

		amdgpu_pm_acpi_event_handler(adev);
	}

	/* Check for pending SBIOS requests */
	return amdgpu_atif_handler(adev, entry);
}

Thanks,
Ryan Lin.

-----Original Message-----
From: Koenig, Christian <Christian.Koenig at amd.com> 
Sent: Friday, March 25, 2022 2:58 PM
To: Lin, Tsung-hua (Ryan) <Tsung-hua.Lin at amd.com>; Wentland, Harry <Harry.Wentland at amd.com>; Li, Sun peng (Leo) <Sunpeng.Li at amd.com>; Deucher, Alexander <Alexander.Deucher at amd.com>; David1.Zhou at amd.com; airlied at linux.ie; daniel at ffwll.ch; seanpaul at chromium.org; bas at basnieuwenhuizen.nl; Kazlauskas, Nicholas <Nicholas.Kazlauskas at amd.com>; sashal at kernel.org; markyacoub at google.com; victorchengchi.lu at amd.com; ching-shih.li at amd.corp-partner.google.com; Siqueira, Rodrigo <Rodrigo.Siqueira at amd.com>; ddavenport at chromium.org; amd-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org; linux-kernel at vger.kernel.org; Li, Leon <Leon.Li at amd.com>
Subject: Re: [PATCH v2 3/25] drm/amdgpu: Disable ABM when AC mode

Am 25.03.22 um 05:05 schrieb Ryan Lin:
> 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 at 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) {

String comparison in a hot path is not something we usually like to see in the kernel.

Isn't there any other way to detect that? Like a flag or similar?

Regards,
Christian.

> +		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;
>   


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