Dss ds docs by akashdeep-ti · Pull Request #732 · TexasInstruments/processor-sdk-doc

akashdeep-ti · 2026-07-03T08:46:48Z

No description provided.

github-actions · 2026-07-03T08:47:43Z

New warnings found with rstcheck:

source/linux/Foundational_Components/Power_Management/pm_am62lx_low_power_modes.rst:177: (WARNING/2) Title underline too short.
source/linux/Foundational_Components/Power_Management/pm_am62lx_low_power_modes.rst:223: (WARNING/2) Title underline too short.
source/linux/Foundational_Components/Power_Management/pm_am62lx_low_power_modes.rst:311: (WARNING/2) Title underline too short.
source/linux/Foundational_Components/Power_Management/pm_am62lx_low_power_modes.rst:335: (ERROR/3) Malformed table.

StaticRocket

Vale comments about passive voice and such

akashdeep-ti · 2026-07-10T10:06:52Z

Addressed code review feedback

kwillis01 · 2026-07-13T21:19:08Z

+DSS plus Deep Sleep
+*******************
+
+DSS plus Deep Sleep is a low-power mode where the Display Subsystem (DSS) is on to display


Maybe "on" should be bolded or in uppercase to make sure the reader understands that it is being used to describe a state

kwillis01 · 2026-07-13T21:23:50Z

+on-chip memory (a small FIFO buffer) instead of continuously fetching from DDR. This
+significantly reduces memory bandwidth and power consumption during suspend.
+
+The AM62L-DSS has a 20 KB FIFO buffer. For the self-refresh feature to work, your static


kwillis01 · 2026-07-13T21:24:37Z

+   **Width × Height × 3 ≤ 20,480 bytes**
+
+For example, a 50×50 RGB image requires 50 × 50 × 3 = 7,500 bytes, which fits comfortably
+within the limit. If your frame is too large, self-refresh will not activate.


kwillis01 · 2026-07-13T21:27:03Z

+
+.. code-block:: console
+
+   root@am62lxx-evm:~# systemctl stop emptty.service


nit: I think you can just do systemctl stop emptty so its a little less to type :)

kwillis01 · 2026-07-13T21:29:27Z

+Using both properties together enables DSS plus Deep Sleep mode: the display shows
+a static frame from internal memory while the rest of the system suspends.


nit: if you wanted to, you could remove these lines since the last sentence of the previous paragraph says the same thing

kwillis01 · 2026-07-14T17:02:16Z

+   [  102.509008] PM: suspend exit
+   root@am62lxx-evm:~#
+
+Resuming from DSS plus Deep Sleep


I think this needs to be named differently since it sounds like resuming from suspend will be described. Maybe rename to something like "Return DSS to Normal Operation"

i think, we can rename to something else, i am not sure about "Normal operation" term as that can vary.
@devarsht , what can be a better alternative?

For the naming of the low power mode ? I would avoid using DSS terminology since its a bit internal to TI.
How about more generic "Always On Display low power mode" this is more generic and intuitive terminology and is already being used in similar context in devices: https://en.wikipedia.org/wiki/Always-on_display

So with this it would be suspending to "Always On Display" low power mode. Resume from "always on display" low power mode.

This also looks better From GOGP Branding POV imho :)

And yeah if you are asking for title then show it as 3 phases

Active Display -> System powered on and HMI Application launched
Low Power Display -> Static Logo with system on low power (inside this mention going to dss deep sleep mode )
Active Display -> Again HMI Application resumed back.

@devarsht The section that the title refers to here is about how to allow the display to show dynamic content again after suspend/resume from DeepSleep + DSS where the display could only show a static image. So would the correct title here be like "Change static display to active display"?

As per above comment, i think its okay to use active display term. i will change static to always on

ti-scaria · 2026-07-15T11:45:56Z

+
+   root@am62lxx-evm:~# modetest -M tidss -w 42:ALWAYS_ON_DISPLAY:1  # 42 is the ALWAYS_ON_DISPLAY CRTC property ID
+
+Configure the system to use s2idle suspend mode, which allows the display to remain powered:


I think this can be a bit misleading.
Display remains powered on because of the always on property, s2idle uses that to select the right low power mode. We can even enter DSS deepsleep if we set the mode=8 in TFA
We should also mention that

i did not understand u mean to say there is a way to still go to dss deep sleep mode even if always on display property is not set ?

mode=8 in TFA -> Isn't this opaque to user i mean they would have to recompile the TFA to do this?

I agree that this sentence is a little confusing. Maybe something along the lines of "Configure the system to use s2idle suspend which will allow the system to enter the lowest power state available. Since the display is configured to be ALWAYS ON, DeepSleep + DSS is the lowest available power state."

Also I don't think we should mention that the mode can be set to 8 in TFA to enter that state since users generally should not do that and the goal of the SDK docs is to show how the SDK is used, rather than modifying it. IMO setting the mode to 8 is more of a debug situation than something a user would do for normal operation.

Yes, I agree we shouldnt mention it here and should advise the use of s2idle
I mentioned this since there is also a [deep] setting to enter LPM which uses the hardcoded value set in TFA, for which we have a note on how RTC+DDR can be entered in this way
Are we planning on removing this from the docs. If not we can expand it to include DSS + Deepsleep as well

devarsht · 2026-07-15T13:10:01Z

+
+.. code-block:: console
+
+   root@am62lxx-evm:~# modetest -M tidss -w 35:SELF_REFRESH:1  # 35 is the SELF_REFRESH plane property ID


35 could change, mention how they can check and get the appropriate number (i..e using kmsprint and modetest command and check for plane id)

Maybe better to keep it simple. Set alwasy on display too here before launching the gstreamer pipe as anyway it would just display one frame after which user can go to low power.

Yes, added more information

devarsht · 2026-07-15T13:44:52Z

+
+   root@am62lxx-evm:~# modetest -M tidss -w 42:ALWAYS_ON_DISPLAY:1  # 42 is the ALWAYS_ON_DISPLAY CRTC property ID
+
+Configure the system to use s2idle suspend mode, which allows the display to remain powered:


i did not understand u mean to say there is a way to still go to dss deep sleep mode even if always on display property is not set ?

mode=8 in TFA -> Isn't this opaque to user i mean they would have to recompile the TFA to do this?

devarsht · 2026-07-15T13:47:47Z

+   [  102.509008] PM: suspend exit
+   root@am62lxx-evm:~#
+
+Resuming from DSS plus Deep Sleep


For the naming of the low power mode ? I would avoid using DSS terminology since its a bit internal to TI.
How about more generic "Always On Display low power mode" this is more generic and intuitive terminology and is already being used in similar context in devices: https://en.wikipedia.org/wiki/Always-on_display

So with this it would be suspending to "Always On Display" low power mode. Resume from "always on display" low power mode.

This also looks better From GOGP Branding POV imho :)

devarsht · 2026-07-15T13:50:42Z

+   Setting pipeline to NULL ...
+   Freeing pipeline ...
+
+After the GStreamer pipeline terminates, the last displayed frame remains on the screen.


Mention that user can press ctrl-c and pipeline will terminate

devarsht · 2026-07-15T14:05:43Z

+
+.. code-block:: console
+
+   root@am62lxx-evm:~# echo mem > /sys/power/state


I think better to try show a more relevant use-case similar to Active Display and Low Power Display use-case we showed in TIEM.

For e.g.

User power on the EVM run HMI Application (this should be present and run by default in procSDK drop)

Now user want to suspend the system and show a static logo,
we set dss to self refresh and we play a command to show a static logo i.e one frame only. (we can play ti logo here I think its present in sdcard)

Then we set always on display and go to dss plus deep sleep mode.

This shows the static logo.

Then we resume back reset the drm props and relaunch the HMI Application.

This can be a separate how to guide too i think if we want to keep this one simple.

IMO for the SDK docs we want as simple as possible so users can understand how to use it easily. However, if the example you wrote is simple to show in the docs, it would probably be the better example to use.

I also agree, we can keep it as a separate guide later. Lets keep this section simple

devarsht · 2026-07-15T14:07:48Z

+   [  102.509008] PM: suspend exit
+   root@am62lxx-evm:~#
+
+Resuming from DSS plus Deep Sleep


And yeah if you are asking for title then show it as 3 phases

Active Display -> System powered on and HMI Application launched
Low Power Display -> Static Logo with system on low power (inside this mention going to dss deep sleep mode )
Active Display -> Again HMI Application resumed back.

devarsht · 2026-07-15T14:22:21Z

+
+   **Width × Height × 3 ≤ 20,480 bytes**
+
+For example, a 50×50 RGB image requires 50 × 50 × 3 = 7,500 bytes, which fits comfortably


take NV12 as an example and what max we can show with this. since we already have less so lets show what max we can show with this.

Got it, updated

devarsht · 2026-07-15T14:22:51Z

      [   88.649913] PM: suspend exit
      root@am62lxx-evm:~#

+DSS plus Deep Sleep


Always On Display?

This cannot be renamed as it is the same terminology used in TIFS documentation also. Also, deep sleep needs to be there in name to make it easily understandable

TIFS Documentation released already ? Hmm i understand deep sleep is more understandable from TI POV but externally from user pov maybe always on display sounds more familiar. Documentation can mention that it is same as deep sleep albeit with display ON.

Add DSS plus Deep Sleep low power mode, a new suspend mode where the Display Subsystem remains powered to show a static image while the rest of the system enters Deep Sleep. Signed-off-by: Akashdeep Kaur <a-kaur@ti.com>

Add power consumption data for DSS plus Deep Sleep mode. This mode consumes more power than standard Deep Sleep (14.07 mW) due to the active display subsystem with FIFO replay. Signed-off-by: Akashdeep Kaur <a-kaur@ti.com>

Add DSS plus Deep Sleep mode to Key Release References section, highlighting the new display subsystem self-refresh capability that allows showing static images during system suspend. Signed-off-by: Akashdeep Kaur <a-kaur@ti.com>

akashdeep-ti requested review from StaticRocket, VeeruPrudhvi, cshilwant, gehariprasath, jeevantelukula, praneethbajjuri and uditkumarti as code owners July 3, 2026 08:46

github-actions Bot assigned bryanbrattlof, devarsht, gehariprasath, praneethbajjuri, r-vignesh, sskartheekadivi, uditkumarti and vishalmti Jul 3, 2026

akashdeep-ti force-pushed the dss_ds_docs branch from 317a2f5 to f7d3760 Compare July 3, 2026 10:01

StaticRocket requested changes Jul 10, 2026

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akashdeep-ti force-pushed the dss_ds_docs branch from f7d3760 to 19a231c Compare July 10, 2026 10:04

cshilwant requested a review from StaticRocket July 10, 2026 19:20

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cshilwant assigned ti-sebin Jul 12, 2026

kwillis01 suggested changes Jul 13, 2026

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akashdeep-ti dismissed StaticRocket’s stale review via 842b96c July 14, 2026 10:30

akashdeep-ti force-pushed the dss_ds_docs branch from 19a231c to 842b96c Compare July 14, 2026 10:30

akashdeep-ti requested a review from kwillis01 July 14, 2026 10:32

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ti-scaria reviewed Jul 15, 2026

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devarsht reviewed Jul 15, 2026

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Comment thread source/linux/Foundational_Components/Power_Management/pm_am62lx_low_power_modes.rst

devarsht reviewed Jul 15, 2026

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devarsht suggested changes Jul 15, 2026

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akashdeep-ti added 3 commits July 16, 2026 13:31

feat(pm_low_power_modes): add DSS plus Deep Sleep mode for AM62LX

aa7fabf

Add DSS plus Deep Sleep low power mode, a new suspend mode where the Display Subsystem remains powered to show a static image while the rest of the system enters Deep Sleep. Signed-off-by: Akashdeep Kaur <a-kaur@ti.com>

feat(linux): add DSS plus Deep Sleep power measurements

9ba4fa6

Add power consumption data for DSS plus Deep Sleep mode. This mode consumes more power than standard Deep Sleep (14.07 mW) due to the active display subsystem with FIFO replay. Signed-off-by: Akashdeep Kaur <a-kaur@ti.com>

akashdeep-ti force-pushed the dss_ds_docs branch from 842b96c to 96f5616 Compare July 16, 2026 08:02

github-actions Bot requested review from bryanbrattlof, r-vignesh, sskartheekadivi and vishalmti July 16, 2026 08:02

kwillis01 approved these changes Jul 16, 2026

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		.. code-block:: console

		root@am62lxx-evm:~# systemctl stop emptty.service

		Using both properties together enables DSS plus Deep Sleep mode: the display shows
		a static frame from internal memory while the rest of the system suspends.


		root@am62lxx-evm:~# modetest -M tidss -w 42:ALWAYS_ON_DISPLAY:1 # 42 is the ALWAYS_ON_DISPLAY CRTC property ID

		Configure the system to use s2idle suspend mode, which allows the display to remain powered:


		.. code-block:: console

		root@am62lxx-evm:~# echo mem > /sys/power/state


		Width × Height × 3 ≤ 20,480 bytes

		For example, a 50×50 RGB image requires 50 × 50 × 3 = 7,500 bytes, which fits comfortably

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akashdeep-ti commented Jul 3, 2026

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akashdeep-ti commented Jul 10, 2026

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kwillis01 Jul 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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kwillis01 Jul 15, 2026 •

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