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

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Message-Id: <8FE329BB-706A-4D16-950C-A7571FE0B40A@canonical.com>
Date:   Thu, 30 Jul 2020 17:50:48 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Marcel Holtmann <marcel@...tmann.org>
Cc:     Abhishek Pandit-Subedi <abhishekpandit@...omium.org>,
        chromeos-bluetooth-upstreaming 
        <chromeos-bluetooth-upstreaming@...omium.org>,
        Bluetooth Kernel Mailing List 
        <linux-bluetooth@...r.kernel.org>,
        Alex Lu <alex_lu@...lsil.com.cn>, linux-pm@...r.kernel.org,
        Johan Hedberg <johan.hedberg@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Revert "Bluetooth: btusb: Disable runtime suspend on
 Realtek devices"



> On Jul 30, 2020, at 15:30, Marcel Holtmann <marcel@...tmann.org> wrote:
> 
> Hi Kai-Heng,
> 
>>> On Jul 30, 2020, at 07:17, Abhishek Pandit-Subedi <abhishekpandit@...omium.org> wrote:
>>> 
>>> 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 issue was found on 8723DE. Do you have one to test with?
>> The rtw88 codebase has changed a lot and maybe it's already fixed in mainline.
>> Let me do some test and I'll report back.
>> 
>>> 
>>> 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.
>> 
>> It's apparently a driver/firmware/hardware issue, so the fix should keep inside the kernel.
>> However, the fix can be more precise and target only 8723DE.
> 
> lets do that and lets do it quickly since the merge window is close. Otherwise I really have to revert that patch.

Ok, I no longer observe the original issue with the patch reverted.
Acked-by: Kai-Heng Feng <kai.heng.feng@...onical.com>

> 
> Regards
> 
> Marcel
>