ACK: [PATCH 0/1][SRU][OEM-5.10] Fix Intel AX210 Wi-Fi [8086:43f0] subsystem [1a56:1652] fw load failure

[Tim Gardner]

Acked-by: Tim Gardner <tim.gardner at canonical.com>

On 3/19/21 5:02 AM, You-Sheng Yang wrote:
> BugLink: https://bugs.launchpad.net/bugs/1913259
> 
> [Impact]
> 
> Intel AX210 Wi-Fi [8086:43f0] subsystem [1a56:1652] requests invalid
> firmware path and fails device init:
> 
>    [ 4.146811] Intel(R) Wireless WiFi driver for Linux
>    [ 4.146866] iwlwifi 0000:00:14.3: enabling device (0000 -> 0002)
>    [ 4.155371] iwlwifi 0000:00:14.3: Direct firmware load for (efault)128.ucode failed with error -2
>    [ 4.155388] iwlwifi 0000:00:14.3: Direct firmware load for (efault)127.ucode failed with error -2
>    ...
>    [ 4.157058] iwlwifi 0000:00:14.3: Direct firmware load for (efault)1.ucode failed with error -2
>    [ 4.157068] iwlwifi 0000:00:14.3: Direct firmware load for (efault)0.ucode failed with error -2
>    [ 4.157070] iwlwifi 0000:00:14.3: no suitable firmware found!
>    [ 4.157071] iwlwifi 0000:00:14.3: minimum version required: (efault)0
>    [ 4.157072] iwlwifi 0000:00:14.3: maximum version supported: (efault)128
>    [ 4.157073] iwlwifi 0000:00:14.3: check git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
> 
> This is a design flaw in iwlwifi driver source.
> 
> In drivers/net/wireless/intel/iwlwifi/pcie/drv.c
> 
>    static const struct pci_device_id iwl_hw_card_ids[] = {
>      {IWL_PCI_DEVICE(0x4232, 0x1201, iwl5100_agn_cfg)},
>      ...
>      {IWL_PCI_DEVICE(0x43F0, PCI_ANY_ID, iwl_qu_long_latency_trans_cfg)},
>      ...
>    };
> 
> The third argument to IWL_PCI_DEVICE macro will be assigned to driver_data field
> of struct pci_device_id. However, iwl5100_agn_cfg has type struct iwl_cfg, and
> yet iwl_qu_long_latency_trans_cfg has type struct iwl_cfg_trans_params.
> 
>    struct iwl_cfg_trans_params {
>      ...
>    };
> 
>    struct iwl_cfg {
>      struct iwl_cfg_trans_params trans;
>      const char *name;
>      const char *fw_name_pre;
>      ...
>    };
> 
> It's fine to cast a pointer to struct iwl_cfg, but it's not always valid to cast
> a struct iwl_cfg_trans_params to struct iwl_cfg.
> 
> In function iwl_pci_probe, it tries to find an alternative cfg by iterating
> throughout iwl_dev_info_table, but in our case, [8086:43f0] subsystem
> [1a56:1652], all of the candidates will be skipped, and
> iwl_qu_long_latency_trans_cfg will be assigned as the ultimate struct iwl_cfg,
> which will be certainly wrong when you're trying to refer to anything beyond
> sizeof(struct iwl_cfg_trans_params), e.g. cfg->fw_name_pre. In this case,
> ((struct iwl_cfg_trans_params*)&iwl_qu_long_latency_trans_cfg)->name will be
> "'", and ((struct iwl_cfg_trans_params*)&iwl_qu_long_latency_trans_cfg)->fw_name_pre
> gives "(efault)", pure garbage data.
> 
> [Fix]
> 
> Commit 410f758529bc ("iwlwifi: add new cards for So and Qu family") in v5.12-rc1
> add a few additional entries to correctly catch this card.
> 
> [Test Case]
> 
> Booting from kernel built with aforementioned commit cherry-picked, WiFi
> interface should be now up and working. Also tested this kernel against several
> iwlwifi supported models on the target and a previous generation platform.
> 
> [Where problems could occur]
> 
> This card failed initialization previously. With it being up and running, it may
> affect system stability if there are some undiscovered bugs related to this new
> model.
> 
> [Other Info]
> 
> This change has been backported to stable kernel v5.11.4, so skipped nomination
> for Hirsute/Unstable.
> 
> Ihab Zhaika (1):
>    iwlwifi: add new cards for So and Qu family
> 
>   .../net/wireless/intel/iwlwifi/cfg/22000.c    | 18 +++++++++++++
>   .../net/wireless/intel/iwlwifi/iwl-config.h   |  3 +++
>   drivers/net/wireless/intel/iwlwifi/pcie/drv.c | 27 +++++++++++++++++++
>   3 files changed, 48 insertions(+)
> 

-- 
-----------
Tim Gardner
Canonical, Inc