linux-kernel - Re: [PATCH] Bluetooth: qca: set power_ctrl_enabled on NULL returned by gpiod_get

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Date: Wed, 24 Apr 2024 05:09:02 -0700
From: Wren Turkal <wt@...guintechs.org>
To: Bartosz Golaszewski <brgl@...ev.pl>
Cc: linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org,
 Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
 Zijun Hu <quic_zijuhu@...cinc.com>, Marcel Holtmann <marcel@...tmann.org>,
 Luiz Augusto von Dentz <luiz.dentz@...il.com>,
 Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Subject: Re: [PATCH] Bluetooth: qca: set power_ctrl_enabled on NULL returned
 by gpiod_get_optional()

On 4/24/24 4:56 AM, Bartosz Golaszewski wrote:
> On Wed, Apr 24, 2024 at 1:53 PM Wren Turkal <wt@...guintechs.org> wrote:
>>
>> On 4/24/24 4:16 AM, Wren Turkal wrote:
>>> On 4/24/24 2:04 AM, Bartosz Golaszewski wrote:
>>>> On Wed, 24 Apr 2024 07:07:05 +0200, Wren Turkal<wt@...guintechs.org>
>>>> said:
>>>>> On 4/22/24 6:00 AM, Bartosz Golaszewski wrote:
>>>>>> From: Bartosz Golaszewski<bartosz.golaszewski@...aro.org>
>>>>>>
>>>>>> Any return value from gpiod_get_optional() other than a pointer to a
>>>>>> GPIO descriptor or a NULL-pointer is an error and the driver should
>>>>>> abort probing. That being said: commit 56d074d26c58 ("Bluetooth:
>>>>>> hci_qca:
>>>>>> don't use IS_ERR_OR_NULL() with gpiod_get_optional()") no longer sets
>>>>>> power_ctrl_enabled on NULL-pointer returned by
>>>>>> devm_gpiod_get_optional(). Restore this behavior but bail-out on
>>>>>> errors.
>>>>> Nack. This patch does fixes neither the disable/re-enable problem nor
>>>>> the warm boot problem.
>>>>>
>>>>> Zijun replied to this patch also with what I think is the proper
>>>>> reasoning for why it doesn't fix my setup.
>>>>>
>>>> Indeed, I only addressed a single issue here and not the code under the
>>>> default: label of the switch case. Sorry.
>>>>
>>>> Could you give the following diff a try?
>>>
>>> I had a feeling that was what was going on. I'll give the patch a shot.
>>>
>>> wt
>>
>> Considering this patch is basically equivalent to patch 1/2 from Zijun,
>> I am not surprised that is works similarly. I.e. on a cold boot, I can
>> disable/re-enable bluetooth as many time as I want.
>>
> 
> Zijun didn't bail out on errors which is the issue the original patch
> tried to address and this one preserves.

Ah, I see that. Yeah, Zijun's 1/2 doesn't have the returns.

>> However, since this patch doesn't include the quirk fix from Zijun's
>> patchset (patch 2/2), bluetooth fails to work after a warm boot.
>>
> 
> That's OK, we have the first part right. Let's now see if we can reuse
> patch 2/2 from Zijun.
> 
>> @Zijun, this patch looks more idiomatic when I look at the surrounding
>> code than your patch 1/2. Notice how it doesn't use the "else if"
>> construct. It does the NULL test separately after checking for errors.
>>
>> --
>> You're more amazing than you think!
> 
> Bart

-- 
You're more amazing than you think!