X11 pen detection: fix misclassification due to improper init

xinput2_device_is_pen() was testing against default-zero values
in the X11 Atom cache on at least the first round of
detections, leading to imprecise detection.

The patch fixes two aspects of initialisation:

1. Ensure that the selector cache is always initialised in
xinput2_device_is_pen().

2. Ensure that all X11 Atoms used in SDL_x11pen.c are instantiated if
missing. This ensures that they are never None and avoids potential
failures to detect hot-plugged tablet devices.

Acknowledgements: @tilman3 for narrowing down the issue and an
initial fix
main
Christoph Reichenbach 2023-11-26 08:47:32 +00:00 committed by Ozkan Sezer
parent c4ca64deaf
commit 1b284cd415
1 changed files with 9 additions and 6 deletions

View File

@ -114,9 +114,9 @@ static void pen_atoms_ensure_initialized(SDL_VideoDevice *_this)
pen_atoms.device_product_id = X11_XInternAtom(data->display, "Device Product ID", False);
pen_atoms.wacom_serial_ids = X11_XInternAtom(data->display, "Wacom Serial IDs", False);
pen_atoms.wacom_tool_type = X11_XInternAtom(data->display, "Wacom Tool Type", False);
pen_atoms.abs_pressure = X11_XInternAtom(data->display, "Abs Pressure", True);
pen_atoms.abs_tilt_x = X11_XInternAtom(data->display, "Abs Tilt X", True);
pen_atoms.abs_tilt_y = X11_XInternAtom(data->display, "Abs Tilt Y", True);
pen_atoms.abs_pressure = X11_XInternAtom(data->display, "Abs Pressure", False);
pen_atoms.abs_tilt_x = X11_XInternAtom(data->display, "Abs Tilt X", False);
pen_atoms.abs_tilt_y = X11_XInternAtom(data->display, "Abs Tilt Y", False);
pen_atoms.initialized = 1;
}
@ -390,9 +390,12 @@ static void xinput2_vendor_peninfo(SDL_VideoDevice *_this, const XIDeviceInfo *d
}
/* Does this device have a valuator for pressure sensitivity? */
static SDL_bool xinput2_device_is_pen(const XIDeviceInfo *dev)
static SDL_bool xinput2_device_is_pen(SDL_VideoDevice *_this, const XIDeviceInfo *dev)
{
int classct;
pen_atoms_ensure_initialized(_this);
for (classct = 0; classct < dev->num_classes; ++classct) {
const XIAnyClassInfo *classinfo = dev->classes[classct];
@ -445,8 +448,8 @@ void X11_InitPen(SDL_VideoDevice *_this)
int old_num_pens_known = pen_map.num_pens_known;
int k;
/* Only track physical devices that are enabled */
if (dev->use != XISlavePointer || dev->enabled == 0 || !xinput2_device_is_pen(dev)) {
/* Only track physical devices that are enabled and look like pens */
if (dev->use != XISlavePointer || dev->enabled == 0 || !xinput2_device_is_pen(_this, dev)) {
continue;
}