Message-ID: <8d8cb631-1d72-436f-ac97-5449ba46ef42@amd.com>
Date: Fri, 21 Nov 2025 10:40:49 +0000
From: Alejandro Lucero Palau <alucerop@....com>
To: PJ Waskiewicz <ppwaskie@...nel.org>, alejandro.lucero-palau@....com,
 linux-cxl@...r.kernel.org, netdev@...r.kernel.org, dan.j.williams@...el.com,
 edward.cree@....com, davem@...emloft.net, kuba@...nel.org,
 pabeni@...hat.com, edumazet@...gle.com, dave.jiang@...el.com
Subject: Re: [PATCH v21 00/23] Type2 device basic support


On 11/21/25 06:41, PJ Waskiewicz wrote:
> On Wed, 2025-11-19 at 19:22 +0000, alejandro.lucero-palau@....com
> wrote:
>
> Hi Alejandro,
>
> Sorry it's been a bit since I've been able to comment.  I've been
> trying to test these patchsets with varying degrees of success.  Still
> haven't gotten things up and running fully.  One comment below.


Hi,


No worries!


>> From: Alejandro Lucero <alucerop@....com>
>>
>> The patchset should be applied on the described base commit then
>> applying
>> Terry's v13 about CXL error handling. The first 4 patches come from
>> Dan's
>> for-6.18/cxl-probe-order branch with minor modifications.
>>
>> v21 changes;
>>
>>    patch1-2: v20 patch1 splitted up doing the code move in the second
>> 	    patch in v21. (Jonathan)
>>   
>>    patch1-4: adding my Signed-off tag along with Dan's
>>
>>    patch5: fix duplication of CXL_NR_PARTITION definition
>>
>>    patch7: dropped the cxl test fixes removing unused function. It was
>> 	  sent independently ahead of this version.
>>
>>    patch12: optimization for max free space calculation (Jonathan)
>>
>>    patch19: optimization for returning on error (Jonathan)
> I cannot test these v21 patches or the v20 patches for the same reason.
> I suspect v19 is also affected, but I was stuck on v17 for awhile (b4
> was really not likely the prereq patches you required to get the tree
> into a usable state to apply your patchset).
>
> When I build and go to install the kernel mods, depmod fails:
>
> DEPMOD  /lib/modules/6.18.0-rc6+
> depmod: ERROR: Cycle detected: cxl_core -> cxl_mem -> cxl_port ->
> cxl_core
> depmod: ERROR: Cycle detected: cxl_core -> cxl_mem -> cxl_core
> depmod: ERROR: Found 3 modules in dependency cycles!
>
> I repro'd this on a few different systems, and just finally repro'd
> this on a box outside of my work network.
>
> This is unusable unfortunately, so I can't test this if I wanted to.


I have been able to reproduce this, and I think after the changes 
introduced in patches 2 & 3, we also need this:



diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index 6b871cbbce13..94a3102ce86b 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -1,6 +1,6 @@
  # SPDX-License-Identifier: GPL-2.0-only
  menuconfig CXL_BUS
-       tristate "CXL (Compute Express Link) Devices Support"
+       bool "CXL (Compute Express Link) Devices Support"
         depends on PCI
         select FW_LOADER
         select FW_UPLOAD


This changes implies neither CXL_BUS optionally being a module nor cxl_mem.


This should be enough for at least you able to test the patchset.


If this is agreed, I will send a v22 with it.


Thank you!


> My .config for CXL:
>
>
> CONFIG_PCIEAER_CXL=y
> CONFIG_CXL_BUS=m
> CONFIG_CXL_PCI=y
> # CONFIG_CXL_MEM_RAW_COMMANDS is not set
> CONFIG_CXL_ACPI=m
> CONFIG_CXL_PMEM=m
> CONFIG_CXL_MEM=m
> CONFIG_CXL_FEATURES=y
> # CONFIG_CXL_EDAC_MEM_FEATURES is not set
> CONFIG_CXL_PORT=m
> CONFIG_CXL_SUSPEND=y
> CONFIG_CXL_REGION=y
> # CONFIG_CXL_REGION_INVALIDATION_TEST is not set
> CONFIG_CXL_RAS=y
> CONFIG_CXL_RCH_RAS=y
> CONFIG_CXL_PMU=m
> CONFIG_DEV_DAX_CXL=m
>
> Pretty simple to repro.
>
> $ make -j<N> && make modules && make modules_install
>
> Hopefully there's a solution here that doesn't involve building the
> whole mess into the kernel directly.
>
> Cheers,
> -PJ

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