Zhiyi Zhang (@zhiyi) commented about dlls/win32u/sysparams.c:
+ struct device_manager_ctx *ctx = param; + + if (!ctx->adapter_count) + { + static const struct gdi_adapter default_adapter = + { + .state_flags = DISPLAY_DEVICE_ATTACHED_TO_DESKTOP | DISPLAY_DEVICE_PRIMARY_DEVICE | DISPLAY_DEVICE_VGA_COMPATIBLE, + }; + TRACE( "adding default fake adapter\n" ); + add_adapter( &default_adapter, ctx ); + } + + if (write_adapter_mode( ctx->adapter_key, ctx->mode_count, mode )) + { + ctx->driver_extra = max( ctx->driver_extra, mode->dmDriverExtra ); + set_reg_value( ctx->adapter_key, driver_extraW, REG_DWORD, &ctx->driver_extra, sizeof(ctx->driver_extra) ); dmDriverExtra should be a fixed value for all modes. So you don't need to call max() and save it to the registry every time.
-- https://gitlab.winehq.org/wine/wine/-/merge_requests/406#note_5025