Warning: These instructions should not be followed blindly since misconfiguration could leave your system in a broken state. The method used for enabling S3 Sleep on my Dell laptop was achieved through patching the stock DSDT ACPI Table provided by my system. DSDT tables are hardware-specific, so yours may very well be different from mine. You will also need to fix DSDT again after each BIOS update and repeat these steps! Use these methods at your own risk. I bear no liability for anything that goes wrong.

As a sneak peek, the “real” change is quite simple, at least on my model. Just change a Zero to a One in a “SS3” variable and Linux will recognize the system as supporting S3 (deep) sleep.

-    Name (SS3, Zero)
+    Name (SS3, One)

Before embarking on this guide, you should probably double-check: does your system already support/advertise S3 (deep) sleep? If the output of the cat /sys/power/mem_sleep command contains “deep”, then your system already supports S3 sleep and you should not follow this guide. There are many resources elsewhere for enabling deep sleep on hardware supporting it, such as via setting the mem_sleep_default GRUB parameter.

This guide has been tested on Ubuntu 24.04, however all instructions (except for those for installing the patched DSDT file) should be distro-agnostic. DSDT tables are hardware-specific, however, and should not be used on hardware that does not exactly match my own. Given the risky nature of DSDT patching, I will emphasize the non-portability of my complete patch several times in this post. Apologies in advance for that repetitiveness.

Table of Contents

Fetching your system’s DSDT Table

Assuming you have not installed a custom DSDT table yet, you can get your system’s reported DSDT table by running the command

cat /sys/firmware/acpi/tables/DSDT > dsdt.dat

To know whether my results will translate exactly, the command sha256sum dsdt.dat should match my output exactly

; sha256sum dsdt.dat 
bf9e3180184d40ee16d52d64cb29dc7820fac59163975c28483e49accba43789  dsdt.dat

If the hashes do not match, don’t dismay. You may still find this guide insightful, but you should not apply my patches as-is.

Disassembly, Reassembly, Patching Errors

To begin, disassemble the dsdt.dat binary to a .dsl file with the command:

iasl -d dsdt.dat

which should produce a dsdt.dsl file.

It is possible that your DSDT table ships with bugs that prevent re-compilation. We first should check for and fix any compilation errors that occur. Compile the disassembled .dsl file with the command:

iasl -tc dsdt.dsl

If there are errors in the compilation, you will see an error at the bottom reading “No AML files were generated due to compiler error(s)”. “Warnings” and “Remarks” are fine, but Errors are fatal.

To find any errors, you can redirect the large output to a file by running iasl -tc dsdt.dsl &> output.txt and open it in less, and search for lines beginning with “Error”. In my case, I had the following 3 Errors:

dsdt.dsl     85:     External (_SB_.PC00.LPCB.ECDV.CMFC.DLPN, UnknownObj)
Error    6163 -                                           ^ Object is created temporarily in another method and cannot be accessed (_SB_.PC00.LPCB.ECDV.CMFC.DLPN)

dsdt.dsl     86:     External (_SB_.PC00.LPCB.ECDV.CMFC.IDMN, UnknownObj)
Error    6163 -                                           ^ Object is created temporarily in another method and cannot be accessed (_SB_.PC00.LPCB.ECDV.CMFC.IDMN)

dsdt.dsl     87:     External (_SB_.PC00.LPCB.ECDV.CMFC.IDPC, UnknownObj)
Error    6163 -                                           ^ Object is created temporarily in another method and cannot be accessed (_SB_.PC00.LPCB.ECDV.CMFC.IDPC)

You will need to fix all issues in the dsdt.dsl file to proceed. To fix my errors, I deleted the following 3 lines problematic lines:

@@ -82,9 +82,6 @@ DefinitionBlock ("", "DSDT", 2, "DELL  ", "Dell Inc", 0x00000002)
     External (_SB_.PC00.ITSP, UnknownObj)
     External (_SB_.PC00.LPCB.ECDV.ACOS, DeviceObj)
     External (_SB_.PC00.LPCB.ECDV.ACSE, DeviceObj)
-    External (_SB_.PC00.LPCB.ECDV.CMFC.DLPN, UnknownObj)
-    External (_SB_.PC00.LPCB.ECDV.CMFC.IDMN, UnknownObj)
-    External (_SB_.PC00.LPCB.ECDV.CMFC.IDPC, UnknownObj)
     External (_SB_.PC00.LPCB.ECDV.DPNT, MethodObj)    // 0 Arguments

Running iasl -tc dsdt.dsl again runs with no errors.

Enabling S3 Sleep Support

After fixing the compilation bugs of the stock Dell ACPI table, there is a single-line change that enables S3 sleep support on my system, namely changing this variable’s value from Zero to One:

-    Name (SS3, Zero)
+    Name (SS3, One)

which now activates the block later in the dsl file:

    If (SS3)
    {
        Name (_S3, Package (0x04)  // _S3_: S3 System State
        {
            0x05, 
            Zero, 
            Zero, 
            Zero
        })
    }

If your .dat hash did not match mine, but your .dsl file contains the SS3 variable definition and a similar if block to the above, then you may be in luck! It might be worth making that single-line change in your .dsl too.

One more patch is necessary – incrementing the version number in the “DefinitionBlock” near the top of the file, so that the patched version is preferred over the OEM. My OEM version is “2” and I have now incremented it to “3”:

-DefinitionBlock ("", "DSDT", 2, "DELL  ", "Dell Inc", 0x00000002)
+DefinitionBlock ("", "DSDT", 2, "DELL  ", "Dell Inc", 0x00000003)

My Final Patch File

Caution: This patch will likely not work on your system without modification. You can double-check your sha256 hash of your raw .dat file with:

; sha256sum dsdt.dat 
bf9e3180184d40ee16d52d64cb29dc7820fac59163975c28483e49accba43789  dsdt.dat

If the hash does not match, do not apply my patch. You can follow the rationale that informed the creation of my patch file (as outlined in the previous sections) to help you craft your own patch file, as long as your .dsl is not too different from mine.

Below is the complete .dsl patch from my system, which can be applied with the command patch < /path/to/patch/file (assuming you are in the directory containing your dsdt.dsl file). I have also included the patch file below for download here: dsdt.dsl.patch

--- dsdt.dsl
+++ dsdt.dsl	2026-05-14 20:45:53.215975289 -0400
@@ -18,7 +18,7 @@
  *     Compiler ID      "    "
  *     Compiler Version 0x01000013 (16777235)
  */
-DefinitionBlock ("", "DSDT", 2, "DELL  ", "Dell Inc", 0x00000002)
+DefinitionBlock ("", "DSDT", 2, "DELL  ", "Dell Inc", 0x00000003)
 {
     External (_GPE.AL6F, MethodObj)    // 0 Arguments
     External (_GPE.HLVT, MethodObj)    // 0 Arguments
@@ -82,9 +82,6 @@
     External (_SB_.PC00.ITSP, UnknownObj)
     External (_SB_.PC00.LPCB.ECDV.ACOS, DeviceObj)
     External (_SB_.PC00.LPCB.ECDV.ACSE, DeviceObj)
-    External (_SB_.PC00.LPCB.ECDV.CMFC.DLPN, UnknownObj)
-    External (_SB_.PC00.LPCB.ECDV.CMFC.IDMN, UnknownObj)
-    External (_SB_.PC00.LPCB.ECDV.CMFC.IDPC, UnknownObj)
     External (_SB_.PC00.LPCB.ECDV.DPNT, MethodObj)    // 0 Arguments
     External (_SB_.PC00.LPCB.ECDV.ECS2, MethodObj)    // 2 Arguments
     External (_SB_.PC00.LPCB.ECDV.ECS3, MethodObj)    // 0 Arguments
@@ -601,7 +598,7 @@
 
     Name (SS1, Zero)
     Name (SS2, Zero)
-    Name (SS3, Zero)
+    Name (SS3, One)
     Name (SS4, One)
     OperationRegion (GNVS, SystemMemory, 0x63904000, 0x0A95)
     Field (GNVS, AnyAcc, Lock, Preserve)

Compiling and Installing the Patched DSDT File

Compiling your new DSDT table is the same as before:

iasl -tc dsdt.dsl

This should produce no Errors. After running the command, you should have a dsdt.aml file which you can now install.

I will largely leave the installation of the DSL file up to you. The Arch Wiki has a good guide on how to do this: https://wiki.archlinux.org/title/DSDT#Using_modified_code. I personally followed their “Using a CPIO archive” instructions to get the modified table installed on my Ubuntu 24.04 system.

When you boot back into Linux after install the patched .aml file, cat /sys/power/mem_sleep should now show [s2idle] deep. Meaning that deep sleep is supported but not enabled (the [] brackets indicate the enabled option). There are a few ways to enable S3 sleep by default, but if you are a GRUB user, adding mem_sleep_default=deep to your /etc/default/grub and running sudo update-grub should enable S3 sleep!

You should now be done! If you added mem_sleep_default=deep to your GRUB config, then S3 sleep should be enabled on your next reboot. You can temporarily enable deep sleep without rebooting via the command echo deep > /sys/power/mem_sleep in a su prompt. When cycling between suspend and resume, you can test that you are entering S3 sleep by running journalctl -k -b -0 | grep "S3\|deep". If all goes well, you should see something like this.

; journalctl -k -b -1 | grep "S3\|deep"

May 14 20:54:38 fredux kernel: ACPI: PM: (supports S0 S3 S4 S5)
May 14 20:55:37 fredux kernel: PM: suspend entry (deep)
May 14 20:55:54 fredux kernel: ACPI: PM: Preparing to enter system sleep state S3
May 14 20:55:54 fredux kernel: ACPI: PM: Waking up from system sleep state S3
May 14 20:56:24 fredux kernel: PM: suspend entry (deep)
May 14 20:56:38 fredux kernel: ACPI: PM: Preparing to enter system sleep state S3
May 14 20:56:38 fredux kernel: ACPI: PM: Waking up from system sleep state S3
May 14 20:57:17 fredux kernel: PM: suspend entry (deep)
May 14 21:03:32 fredux kernel: ACPI: PM: Preparing to enter system sleep state S3
May 14 21:03:32 fredux kernel: ACPI: PM: Waking up from system sleep state S3
May 14 21:04:02 fredux kernel: PM: suspend entry (deep)
May 14 21:09:38 fredux kernel: ACPI: PM: Preparing to enter system sleep state S3
May 14 21:09:38 fredux kernel: ACPI: PM: Waking up from system sleep state S3
May 14 21:48:29 fredux kernel: PM: suspend entry (deep)
May 14 21:52:40 fredux kernel: ACPI: PM: Preparing to enter system sleep state S3
May 14 21:52:40 fredux kernel: ACPI: PM: Waking up from system sleep state S3

Epilogue

Did this work for your Dell Vostro 3500? Did you see a “one-line” fix similar to mine? Leave a comment below!

I also appreciate any feedback on this post, or any edits you suggest I make. I am very new to ACPI tinkering, with experience only through working with the T2 Linux folks, so please correct me if I got something wrong! Given the hardware-specificity of my patch, it is tough for me to provide general support for enabling S3 sleep on Dell machines, so apologies if I don’t reply to all comments asking for support.

Thanks for reading! I hope this guide helped you.