Re: [PATCH] sh: maple: fix empty port handling

From: Florian Fuchs

Date: Wed Nov 12 2025 - 17:46:45 EST


Hi Artur,
thank you so much for fixing the DC boot on linux again!
Adrian, thank you for looking at it!

On 12 Nov 22:46, Artur Rojek wrote:
> thanks for the patch! Can this be tested with just regular controllers?

Yes, indeed you can test it with the controller, when you compile with
joystick support, like:

CONFIG_MAPLE=y
CONFIG_INPUT=y
CONFIG_INPUT_JOYDEV=y
CONFIG_INPUT_EVDEV=y
CONFIG_INPUT_JOYSTICK=y
CONFIG_JOYSTICK_MAPLE=y

You should not put a VMU in though, as thats currently broken (I have a
patch ready).

Then you can directly read from the evdev and listen for the button
presses:
bash-5.3# cat /dev/input/event2 | xxd

You need to press a button for 20-30 times, as it seems to buffer the
events and outputs it in batches.

Then, you should see the following outputs for the buttons:

Button A:
00000000: 7800 0000 94c3 0d00 0100 3001 0000 0000 x.........0.....
Button B:
000001e0: 7800 0000 94c3 0d00 0100 3101 0100 0000 x.........1....
Button X:
000003b0: 7800 0000 94c3 0d00 0100 3301 0100 0000 x.........3.....
Button Y:
00000900: 7800 0000 94c3 0d00 0100 3401 0100 0000 x.........4.....

The Joystick should be detected like this:
/ # dmesg|grep maple
maple: bus core now registered
maple (null): detected Dreamcast Controller: function 0x1: at (2, 0)
maple (null): no driver found
input: Dreamcast Controller as /devices/maple/2:00.1/input/input2

Another indicator is the dmesg log for empty ports:
maple (null): no devices to port 3

These messages were previously not there, as the empty ports were never
detected.

btw, I have also a cdi file, that boots for me, although I heard there
were issues on the NTSC-U devices, if helpful:
https://github.com/foxdrodd/dreamcast-linux/releases/download/6.17.7/linux6177-joystick.cdi

Thank you for your efforts,
Florian