Re: [PATCH] wifi: iwlwifi: acpi/dsm: cache error retcode for iwl_acpi_get_dsm
From: David Wang
Date: Tue Aug 27 2024 - 03:35:29 EST
At 2024-08-27 14:26:42, "Kalle Valo" <kvalo@xxxxxxxxxx> wrote:
>David Wang <00107082@xxxxxxx> writes:
>
>> On some HW, acpi _DSM query would failed for iwlwifi device
>> and everytime when network is reactiaved (boot,
>> suspend/resume, manually restart network, etc.),
>> bunch of kernel warning shows up together:
>> ACPI: \: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade (0x1001)
>> ACPI: \: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade (0x1001)
>> ACPI: \: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade (0x1001)
>> ACPI: \: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade (0x1001)
>> ACPI: \: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade (0x1001)
>> ACPI: \: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade (0x1001)
>> ACPI: \: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade (0x1001)
>> ACPI: \: failed to evaluate _DSM bf0212f2-788f-c64d-a5b3-1f738e285ade (0x1001)
>> since iwlwifi would make 8 acpi/dsm queries for lari config.
>> But for iwlwifi, it is safe to cache the _DSM errors,
>> since it is not possible to correct it without upgrading BIOS.
>> With this patch, those kernel warnings would only show up once when
>> booting the system and unnecessary acpi/dsm queries are avoid.
>>
>> Signed-off-by: David Wang <00107082@xxxxxxx>
>> ---
>> drivers/net/wireless/intel/iwlwifi/fw/acpi.c | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/drivers/net/wireless/intel/iwlwifi/fw/acpi.c b/drivers/net/wireless/intel/iwlwifi/fw/acpi.c
>> index 79774c8c7ff4..3f98f522daac 100644
>> --- a/drivers/net/wireless/intel/iwlwifi/fw/acpi.c
>> +++ b/drivers/net/wireless/intel/iwlwifi/fw/acpi.c
>> @@ -30,6 +30,8 @@ static const size_t acpi_dsm_size[DSM_FUNC_NUM_FUNCS] = {
>> [DSM_FUNC_ENABLE_11BE] = sizeof(u32),
>> };
>>
>> +static int acpi_dsm_func_retcode[DSM_FUNC_NUM_FUNCS] = {0};
>> +
>> static int iwl_acpi_get_handle(struct device *dev, acpi_string method,
>> acpi_handle *ret_handle)
>> {
>> @@ -169,6 +171,10 @@ int iwl_acpi_get_dsm(struct iwl_fw_runtime *fwrt,
>> if (WARN_ON(func >= ARRAY_SIZE(acpi_dsm_size)))
>> return -EINVAL;
>>
>> + /* If HW return an error once, do not bother try again. */
>> + if (acpi_dsm_func_retcode[func])
>> + return acpi_dsm_func_retcode[func];
>
>Static variables are usually avoided because they are problematic if
>there are multiple iwlwifi devices on the same host. Should the error
>message be just removed entirely?
Thanks for the review~
Yep, you're quite right! I did not consider multiple iwlwifi devices.
The repeated error messages really bother me, but they are from acpi driver, I don't think it can be removed entirely....
Would moving the cache into device structure acceptable?
Thanks
David
>
>--
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>
>https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches