linux-kernel - [PATCH] Revert "Bluetooth: btusb: Disable runtime suspend on Realtek devices"

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Message-Id: <20200729161740.1.Ib03d0827c8e48fc3df887fec698f79fa335c9274@changeid>
Date:   Wed, 29 Jul 2020 16:17:43 -0700
From:   Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
To:     marcel@...tmann.org
Cc:     chromeos-bluetooth-upstreaming@...omium.org,
        Kai-Heng Feng <kai.heng.feng@...onical.com>,
        linux-bluetooth@...r.kernel.org, Alex Lu <alex_lu@...lsil.com.cn>,
        linux-pm@...r.kernel.org,
        Abhishek Pandit-Subedi <abhishekpandit@...omium.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] Revert "Bluetooth: btusb: Disable runtime suspend on Realtek devices"

This reverts commit 7ecacafc240638148567742cca41aa7144b4fe1e.

Testing this change on a board with RTL8822CE, I found that enabling
autosuspend has no effect on the stability of the system. The board
continued working after autosuspend, suspend and reboot.

The original commit makes it impossible to enable autosuspend on working
systems so it should be reverted. Disabling autosuspend should be done
via module param or udev in userspace instead.

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
---
We have a few Chromebooks using the RTL 8822CE part over USB and they
are running without problems with autosuspend enabled. While bringing up
a new board, I found some power regressions that I was able to narrow
down to this change so I'm requesting a revert.

I tested this on Hp Chromebook 14a (running 4.14 kernel and 5.4 kernel)
with this revert:
* Enabled autosuspend, used it normally with a HID device
* Suspended the Chromebook and verified it worked normally on resume
* Rebooted the Chromebook and verified Bluetooth was working on next
  boot

I didn't see the issue that was originally reported with this fix. For
the original reporter, if you're still seeing this issue, there are
other ways to disable autosuspend for your device:
* set module param: enable_autosuspend=0
* change your kconfig so BT_HCIBTUSB_AUTOSUSPEND=n
* use a udev rule to disable autosuspend for specific vid:pid

Keeping this change in the kernel makes it impossible to enable
autosuspend so it should be reverted.

 drivers/bluetooth/btusb.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 1f51494f581812..8d2608ddfd0875 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -4086,10 +4086,6 @@ static int btusb_probe(struct usb_interface *intf,
 			set_bit(BTUSB_USE_ALT1_FOR_WBS, &data->flags);
 		else
 			bt_dev_err(hdev, "Device does not support ALT setting 1");
-
-		err = usb_autopm_get_interface(intf);
-		if (err < 0)
-			goto out_free_dev;
 	}

 	if (!reset)
-- 
2.28.0.rc0.142.g3c755180ce-goog