[PATCH v2 5/5] iwlwifi: mvm: don't use SAR Geo if basic SAR is not used

[Luca Coelho <luca@coelho.fi>]

From: Luca Coelho <luciano.coelho@intel.com>

We can't use SAR Geo if basic SAR is not enabled, since the SAR Geo
tables define offsets in relation to the basic SAR table in use.

To fix this, make iwl_mvm_sar_init() return one in case WRDS is not
available, so we can skip reading WGDS entirely.

Fixes: a6bff3cb19b7 ("iwlwifi: mvm: add GEO_TX_POWER_LIMIT cmd for geographic tx power table")
Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
---
In v2:
   * fix compilation when CONFIG_ACPI is not set;

drivers/net/wireless/intel/iwlwifi/mvm/fw.c | 36 ++++++++++++++++-----
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
index 899f4a6432fb..2ba890445c35 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
@@ -928,6 +928,11 @@ static int iwl_mvm_sar_get_ewrd_table(struct iwl_mvm *mvm)
 	return -ENOENT;
 }
 
+static int iwl_mvm_sar_get_wgds_table(struct iwl_mvm *mvm)
+{
+	return -ENOENT;
+}
+
 static int iwl_mvm_sar_geo_init(struct iwl_mvm *mvm)
 {
 	return 0;
@@ -954,8 +959,11 @@ static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
 		IWL_DEBUG_RADIO(mvm,
 				"WRDS SAR BIOS table invalid or unavailable. (%d)\n",
 				ret);
-		/* if not available, don't fail and don't bother with EWRD */
-		return 0;
+		/*
+		 * If not available, don't fail and don't bother with EWRD.
+		 * Return 1 to tell that we can't use WGDS either.
+		 */
+		return 1;
 	}
 
 	ret = iwl_mvm_sar_get_ewrd_table(mvm);
@@ -968,9 +976,13 @@ static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
 	/* choose profile 1 (WRDS) as default for both chains */
 	ret = iwl_mvm_sar_select_profile(mvm, 1, 1);
 
-	/* if we don't have profile 0 from BIOS, just skip it */
+	/*
+	 * If we don't have profile 0 from BIOS, just skip it.  This
+	 * means that SAR Geo will not be enabled either, even if we
+	 * have other valid profiles.
+	 */
 	if (ret == -ENOENT)
-		return 0;
+		return 1;
 
 	return ret;
 }
@@ -1168,11 +1180,19 @@ int iwl_mvm_up(struct iwl_mvm *mvm)
 		iwl_mvm_unref(mvm, IWL_MVM_REF_UCODE_DOWN);
 
 	ret = iwl_mvm_sar_init(mvm);
-	if (ret)
-		goto error;
+	if (ret == 0) {
+		ret = iwl_mvm_sar_geo_init(mvm);
+	} else if (ret > 0 && !iwl_mvm_sar_get_wgds_table(mvm)) {
+		/*
+		 * If basic SAR is not available, we check for WGDS,
+		 * which should *not* be available either.  If it is
+		 * available, issue an error, because we can't use SAR
+		 * Geo without basic SAR.
+		 */
+		IWL_ERR(mvm, "BIOS contains WGDS but no WRDS\n");
+	}
 
-	ret = iwl_mvm_sar_geo_init(mvm);
-	if (ret)
+	if (ret < 0)
 		goto error;
 
 	iwl_mvm_leds_sync(mvm);
-- 
2.19.1