W541 board: document known ram init issues

Proper documentation of the known issues is a precondition for moving this board back to tested in a previous commit.

Signed-off-by: gaspar-ilom <gasparilom@riseup.net>

Author: gaspar-ilom

blobs/w541/README.md

@@ -8,6 +8,7 @@
 Coreboot on the W541 requires the following binary blobs:
 
 - `mrc.bin` - Consists of Intel’s Memory Reference Code (MRC) and [is used to initialize the DRAM](https://doc.coreboot.org/northbridge/intel/haswell/mrc.bin.html).
+  - Known issues with ram initilization are listed below.
 - `me.bin` - Consists of Intel’s Management Engine (ME), which we modify using [me_cleaner](https://github.com/corna/me_cleaner) to remove all but the modules which are necessary for the CPU to function.
 - `gbe.bin` - Consists of hardware/software configuration data for the Gigabit Ethernet (GbE) controller. Intel publishes the data structure [here](https://web.archive.org/web/20230122164346/https://www.intel.com/content/dam/www/public/us/en/documents/design-guides/i-o-controller-hub-8-9-nvm-map-guide.pdf), and an [ImHex](https://github.com/WerWolv/ImHex) hex editor pattern is available [here](https://github.com/rbreslow/ImHex-Patterns/blob/rb/intel-ich8/patterns/intel/ich8_lan_nvm.hexpat).
 - `ifd.bin` - Consists of the Intel Flash Descriptor (IFD). Intel publishes the data structure [here](https://web.archive.org/web/20221208011432/https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/io-controller-hub-8-datasheet.pdf), and an ImHex hex editor pattern is available [here](https://github.com/rbreslow/ImHex-Patterns/blob/rb/intel-ich8/patterns/intel/ich8_flash_descriptor.hexpat).
@@ -38,3 +39,7 @@ Now, you can rebuild Heads:
 ```console
 $ make BOARD=w541-hotp-maximized
 ```
+
+# Known Issues
+- Ram initialization with the MRC blob is very slow (~40s until boot splash) and so far native ram init (NRI) which was merged upstream has not been able to resolve the issue under heads. Work on HRI is tracked here: https://github.com/linuxboot/heads/pull/1923
+- S3 resume from suspend has been reported as flaky on some boards (4 DIMMs with a total of 32GB ram).

boards/EOL_w541-hotp-maximized/EOL_w541-hotp-maximized.config

@@ -1,5 +1,6 @@
 # WARNING: This system remains perpetually vulnerable to Spectre v2 (CVE-2017-5715). Mitigations and microcode updates previously applied are now known to be ineffective due to QSB-107 and related CVEs. If Spectre v2 is a concern in your threat model, consider migrating to a platform with ongoing microcode support. Proper OPSEC for Memory Use MUST be followed:https://www.anarsec.guide/posts/qubes/#appendix-opsec-for-memory-use
 # Configuration for a ThinkPad W541 with HOTP security dongle support
+# For known issues see the blobs/w541/README.md
 CONFIG_COREBOOT_CONFIG=config/coreboot-w541.config
 # TODO: Make a ThinkPad-common Linux config file.
 CONFIG_LINUX_CONFIG=config/linux-w541.config

boards/EOL_w541-maximized/EOL_w541-maximized.config

@@ -1,5 +1,6 @@
 # WARNING: This system remains perpetually vulnerable to Spectre v2 (CVE-2017-5715). Mitigations and microcode updates previously applied are now known to be ineffective due to QSB-107 and related CVEs. If Spectre v2 is a concern in your threat model, consider migrating to a platform with ongoing microcode support. Proper OPSEC for Memory Use MUST be followed:https://www.anarsec.guide/posts/qubes/#appendix-opsec-for-memory-use
 # Configuration for a ThinkPad W541 without HOTP security dongle support
+# For known issues see the blobs/w541/README.md
 CONFIG_COREBOOT_CONFIG=config/coreboot-w541.config
 # TODO: Make a ThinkPad-common Linux config file.
 CONFIG_LINUX_CONFIG=config/linux-w541.config