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

Lin, Tsung-hua (Ryan) Tsung-hua.Lin at amd.com
Mon Mar 28 01:29:50 UTC 2022


[AMD Official Use Only]

Hi Harry,

I have been reminded to do some modifications to the patch format. So the 3/25 it's the date I resent the mail v2.
If the mail title usage is not correct, please let me know.

And about the questions:
" This file lives in DC, which is shared code between Windows and Linux. We cannot directly use adev here. Any information needs to go through DC structs."
	- I use the adev here because I just reference the code I found in the same function. 

 +	if (strcmp(entry->device_class, "battery") == 0) {                             <-------- I added.
 +		adev->pm.ac_power = power_supply_is_system_supplied() > 0;
 +	}
 +
  	if (strcmp(entry->device_class, ACPI_AC_CLASS) == 0) {                  <-------- I found.
  		if (power_supply_is_system_supplied() > 0)
  			DRM_DEBUG_DRIVER("pm: AC\n");

	-And the reason why I need to add another comparison is that the string of the device_class I got is always "battery" when I plug/unplug the ac cable.
	 It never reports "ac_adapter" to me. So I add the "battery" line to do that.


"I seem to remember someone saying that ABM gets disabled on Windows when we're in AC mode. Have you checked with our Windows guys about this? I feel we're re-inventing the wheel here for no good reason."

	-Yes, I have asked the Windows guys and they told me the ABM should be disabled in AC mode. But seems we don’t have this function on Linux, so I implemented this to disable ABM in AC mode.

Thanks,
Ryan Lin.


-----Original Message-----
From: Wentland, Harry <Harry.Wentland at amd.com> 
Sent: Friday, March 25, 2022 10:46 PM
To: Lin, Tsung-hua (Ryan) <Tsung-hua.Lin at amd.com>; Li, Sun peng (Leo) <Sunpeng.Li at amd.com>; Deucher, Alexander <Alexander.Deucher at amd.com>; Koenig, Christian <Christian.Koenig 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



On 2022-03-25 00:05, Ryan Lin wrote:
> Disable ABM feature when the system is running on AC mode to get the 
> more perfect contrast of the display.

It says patch 3 out of 25. Are there other patches? If so, I can't find them in my mailbox and neither can patchwork https://patchwork.freedesktop.org/series/101767/
 
> 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) {
> +		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) {

This file lives in DC, which is shared code between Windows and Linux. We cannot directly use adev here. Any information needs to go through DC structs.

I seem to remember someone saying that ABM gets disabled on Windows when we're in AC mode. Have you checked with our Windows guys about this? I feel we're re-inventing the wheel here for no good reason.

Harry

> +		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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