linux-kernel - Re: [PATCH v2] hid-playstation: DS4: Update rumble and lightbar together

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Message-ID: <1ff1239d-2f90-4c8d-8b68-b0e0fa2340da@enpas.org>
Date: Thu, 15 Aug 2024 01:40:31 +0900
From: Max Staudt <max@...as.org>
To: Roderick Colenbrander <thunderbird2k@...il.com>
Cc: Roderick Colenbrander <roderick.colenbrander@...y.com>,
 Jiri Kosina <jikos@...nel.org>,
 Benjamin Tissoires <benjamin.tissoires@...hat.com>,
 linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
 nathaniel.lewis@...y.com
Subject: Re: [PATCH v2] hid-playstation: DS4: Update rumble and lightbar
 together

Great, thank you!

Then I guess the previous patch was just too hard to understand. Lesson 
learned, I'll try to be clearer next time :)


On another note, I've dumped hid->rdesc for my controller which shows 
this problem. It is different from my Sony DS4 2.0 controllers, which 
all have the same descriptor. Do you prefer to guard this hack by a 
quirk, which activates on, say, a CRC32 match of the HID descriptor?


Thank you, and sorry for the extended back and forth!

Max




On 8/15/24 01:17, Roderick Colenbrander wrote:
> Hi Max,
> 
> That looks like a reasonable workaround. I think it would be fine to
> add. We will try to support that with Android as well.
> 
> Thanks,
> Roderick
> 
> On Sun, Aug 11, 2024 at 6:15 AM Max Staudt <max@...as.org> wrote:
>>
>> Some 3rd party gamepads expect updates to rumble and lightbar together,
>> and setting one may cancel the other.
>>
>> Let's maximise compatibility by always sending rumble and lightbar
>> updates together, even when only one has been scheduled.
>>
>> Further background reading:
>>
>> - Apparently the PS4 always sends rumble and lightbar updates together:
>>
>>    https://eleccelerator.com/wiki/index.php?title=DualShock_4#0x11_2
>>
>> - 3rd party gamepads may not implement lightbar_blink, and may simply
>>    ignore updates with 0x07 set, according to:
>>
>>    https://github.com/Ryochan7/DS4Windows/pull/1839
>> ---
>> Changes in v1 -> v2:
>>   - Simplified the code, comment, and commit message.
>> ---
>>   drivers/hid/hid-playstation.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
>>
>> diff --git a/drivers/hid/hid-playstation.c b/drivers/hid/hid-playstation.c
>> index e7c309cfe3a0..0d90d7ee693c 100644
>> --- a/drivers/hid/hid-playstation.c
>> +++ b/drivers/hid/hid-playstation.c
>> @@ -2143,6 +2143,26 @@ static void dualshock4_output_worker(struct work_struct *work)
>>
>>          spin_lock_irqsave(&ds4->base.lock, flags);
>>
>> +       /*
>> +        * Some 3rd party gamepads expect updates to rumble and lightbar
>> +        * together, and setting one may cancel the other.
>> +        *
>> +        * Let's maximise compatibility by always sending rumble and lightbar
>> +        * updates together, even when only one has been scheduled, resulting
>> +        * in:
>> +        *
>> +        *   ds4->valid_flag0 >= 0x03
>> +        *
>> +        * Hopefully this will maximise compatibility with third-party pads.
>> +        *
>> +        * Any further update bits, such as 0x04 for lightbar blinking, will
>> +        * be or'd on top of this like before.
>> +        */
>> +       if (ds4->update_rumble || ds4->update_lightbar) {
>> +               ds4->update_rumble = true; /* 0x01 */
>> +               ds4->update_lightbar = true; /* 0x02 */
>> +       }
>> +
>>          if (ds4->update_rumble) {
>>                  /* Select classic rumble style haptics and enable it. */
>>                  common->valid_flag0 |= DS4_OUTPUT_VALID_FLAG0_MOTOR;
>> --
>> 2.39.2
>>
>>