linux-kernel - [PATCH 3/3] Bluetooth: btmrvl_sdio: Power down when suspending

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Message-Id: <20201118154349.3.If6a8ea0def7ff7a1f6a8ba349b9c840201b1d1f0@changeid>
Date:   Wed, 18 Nov 2020 15:43:52 -0800
From:   Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
To:     marcel@...tmann.org, linux-bluetooth@...r.kernel.org
Cc:     chromeos-bluetooth-upstreaming@...omium.org, mcchou@...omium.org,
        danielwinkler@...omium.org,
        Abhishek Pandit-Subedi <abhishekpandit@...omium.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] Bluetooth: btmrvl_sdio: Power down when suspending

After seeing a large number of suspend failures due to -EBUSY, the most
common cause for failure seems to be the log snippet below:

[ 4764.773873] Bluetooth: hci_cmd_timeout() hci0 command 0x0c14 tx timeout
[ 4767.777897] Bluetooth: btmrvl_enable_hs() Host sleep enable command failed
[ 4767.777920] Bluetooth: btmrvl_sdio_suspend() HS not actived, suspend failed!
[ 4767.777946] dpm_run_callback(): pm_generic_suspend+0x0/0x48 returns -16
[ 4767.777963] call mmc2:0001:2+ returned -16 after 4882288 usecs

Since the sleep command is timing out, this points to the firmware as
the most likely source of the problem and we don't have a way to address
the fix there (this is an old controller). So, to mitigate this issue,
we can simply power down the Bluetooth controller when entering suspend
and power it back up when exiting suspend. We control setting this quirk
via a module parameter, power_down_suspend (which defaults to false).

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
---

 drivers/bluetooth/btmrvl_sdio.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/bluetooth/btmrvl_sdio.c b/drivers/bluetooth/btmrvl_sdio.c
index 33d58b30c5acfc..e2e4917b4fe589 100644
--- a/drivers/bluetooth/btmrvl_sdio.c
+++ b/drivers/bluetooth/btmrvl_sdio.c
@@ -35,6 +35,12 @@
 
 #define VERSION "1.0"
 
+/* Add module param to control whether the controller is powered down during
+ * suspend. Default is False.
+ */
+static bool power_down_suspend;
+module_param(power_down_suspend, bool, 0644);
+
 static struct memory_type_mapping mem_type_mapping_tbl[] = {
 	{"ITCM", NULL, 0, 0xF0},
 	{"DTCM", NULL, 0, 0xF1},
@@ -1587,6 +1593,10 @@ static int btmrvl_sdio_probe(struct sdio_func *func,
 		goto disable_host_int;
 	}
 
+	if (power_down_suspend)
+		set_bit(HCI_QUIRK_POWER_DOWN_SYSTEM_SUSPEND,
+			&priv->btmrvl_dev.hcidev->quirks);
+
 	return 0;
 
 disable_host_int:
-- 
2.29.2.299.gdc1121823c-goog