On 12/26/24 5:54 AM, Eugeny Shcheglov wrote: > Hi, Vicki, > > First, I should explain the motivation behind this change. I'm a developer of a gaming platform based on SteamDeck. My app runs in kiosk mode, and the system boots directly into the app, so I need to be able to read Gamepad values by default. > > Let's ensure that we are on the same page and that I understand the driver behavior correctly. > > There is one hardware mode: "Gamepad" mode (probably we can call it something like a "Full" mode), where all inputs from buttons, pads, and switches are processed. "Lizard Mode" is a possibility to filter input, right? So, if Lizard Mode is enabled, it gives us a > possibility to change modes between Gamepad (full input) and Desktop (mouse/keyboard only) by pressing the "Options" button OR automatically when the Steam client is opened. This is not at all accurate. Lizard mode is handled by firmware in the controller board itself and when enabled emulates a keyboard and mouse in addition to the gamepad controls. If lizard mode is disabled, then that emulation is disabled. Game/desktop modes are handled exclusively in the driver. They do different filtering of inputs based on if the evdev node is open or not. I forget the exact specifics and would need to review the code. If you want fine control over how all of this works, you can open the hidraw manually and parse it. The format is well-documented in the driver, and opening the hidraw disables all of this stuff (though you will need to send the heartbeat manually to keep lizard mode off--it automatically turns back on if a watchdog turns off). > >> Switching between gamepad and desktop modes is already blocked when lizard_mode is disabled. See line 1053 in steam_mode_switch_cb. > > No, it doesn't. Mode switching happens on line 1052, right before the "if (!lizard_mode) return" condition in the steam_mode_switch_cb. Oh, yes, come to think of it that should probably be on the other side of that early return. > > Logically, the "lizard_mode=0" option should disable the possibility to filter the input. However, when I tried setting "lizard_mode=0" on my SteamDeck, nothing changed except that the mouse was gone, along with the haptic pulse during mode switching. I'm still able to switch the joystick inputs on and off. Yup, that's because lizard mode is literally just the keyboard/mouse emulation. Since without that desktop mode is useless, it disables the mode changing. Or it should. It looks like that might not be handled entirely correctly, as you just said. > >> All in all, this patch doesn't actually "fix" anything. > > Well, in that case, what should "lizard_mode=0" do? As I mentioned before, on my SteamDeck, it only disables the haptic pulse and "desktop mode" functionality like mouse input. Vicki
