2020-03-15 09:28:03

by Jonathan McDowell

Subject: [PATCH] iwlwifi: mvm: Avoid use of GEO_TX_POWER_LIMIT when not supported

Commit 39c1a9728f93 refactored the SAR table support and inadvertently
added a call to GEO_TX_POWER_LIMIT without checking that the firmware
supported it. This caused a regression for device + firmware
combinations lacking the support. Add a check in iwl_mvm_sar_init to
prevent this.

Fixes: 39c1a9728f93 (iwlwifi: refactor the SAR tables from mvm to acpi)
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206395
Cc: [email protected] # 5.5
Signed-Off-By: Jonathan McDowell <[email protected]>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
index 54c094e88474..4a8a4cb2c553 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
@@ -1007,6 +1007,13 @@ static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
if (ret == -ENOENT)
return 1;

+ /*
+ * If our firmware doesn't support GEO_TX_POWER_LIMIT then skip trying
+ * to use it.
+ */
+ if (!iwl_sar_geo_support(&mvm->fwrt))
+ return 1;
+
return ret;
}


--
... Don't do it!

2020-03-17 10:22:23

by Luca Coelho

Subject: Re: [PATCH] iwlwifi: mvm: Avoid use of GEO_TX_POWER_LIMIT when not supported

On Sat, 2020-03-14 at 10:57 +0000, Jonathan McDowell wrote:
> Commit 39c1a9728f93 refactored the SAR table support and inadvertently
> added a call to GEO_TX_POWER_LIMIT without checking that the firmware
> supported it. This caused a regression for device + firmware
> combinations lacking the support. Add a check in iwl_mvm_sar_init to
> prevent this.
>
> Fixes: 39c1a9728f93 (iwlwifi: refactor the SAR tables from mvm to acpi)
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206395
> Cc: [email protected] # 5.5
> Signed-Off-By: Jonathan McDowell <[email protected]>
>
> diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
> index 54c094e88474..4a8a4cb2c553 100644
> --- a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
> +++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
> @@ -1007,6 +1007,13 @@ static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
> if (ret == -ENOENT)
> return 1;
>
> + /*
> + * If our firmware doesn't support GEO_TX_POWER_LIMIT then skip trying
> + * to use it.
> + */
> + if (!iwl_sar_geo_support(&mvm->fwrt))
> + return 1;
> +
> return ret;
> }

Thanks, Jonathan! We already have an internal patch that fixes this
(also fixes another symptom of the same bug). I'll send it out now.

--
Cheers,
Luca.