Hi Denis, -----Original Message----- From: directfb-dev-boun...@directfb.org [mailto:directfb-dev-boun...@directfb.org] On Behalf Of Denis Oliver Kropp Sent: Saturday, November 17, 2012 5:15 PM To: directfb-dev@directfb.org Subject: Re: [directfb-dev] About commit 'wm/default: use DSFLIP_WAITFORSYNC in DLBM_BACKVIDEO case' and mouse cursor motion lag
On 10/02/12 18:55, Ilyes Gouta wrote: >> Hi Andi, >> >> This is about the commit 2cc44cc, where it changes >> wm_update_cursor()'s dfb_layer_region_flip_update() to take >> DSFLIP_WAITFORSYNC instead of a DSFLIP_NONE. >> >> The callstack when an input event is dispatched via >> dfb_input_dispatch() is as follow: >> >> _dfb_windowstack_inputdevice_listener(); >> dfb_wm_process_input(); >> wm_local->funcs->ProcessInput() -> wm_process_input(); >> flush_motion(); >> perform_motion(); >> dfb_windowstack_cursor_warp(); >> dfb_wm_update_cursor(); >> wm_local->funcs->UpdateCursor() -> wm_update_cursor(); >> >> Then within wm_update_cursor(): >> Line 4385: case DLBM_BACKVIDEO: >> Line 4387: dfb_layer_region_flip_update( primary, NULL, DSFLIP_WAITFORSYNC ); >> >> Wouldn't DSFLIP_WAITFORSYNC cause input handling to delayed since >> wm_update_cursor() is called within the context of >> _dfb_windowstack_inputdevice_listener()? DSFLIP_WAITFORSYNC will block >> for a VSYNC period before returning and that's a interval where the >> input events won't be consumed, leading to a mouse cursor motion lag >> (DirectFB single-mode, default wm)? >> >> Would it make sense to perform the dfb_layer_region_flip_update( >> primary, NULL, DSFLIP_WAITFORSYNC ) in the context of another thread, >> besides 'Fusion Dispatch' (which serves >> _dfb_windowstack_inputdevice_listener())? > You are correct, blocking the dispatch thread is not really acceptable. > We were aware of that issue and planned to fix that soon. One approach is to enable the integration of h/w cursor in DirectFB: so the window manager still listens for the mouse input but instead of rendering the cursor via s/w, it calls into a new system module API to just rely the new cursor coordinates. For ex: the Linux framebuffer interface has an ioctl() for uploading a cursor bitmap and coordinates, etc. -Ilyes -- Denis Oliver Kropp DirectFB integrated media GmbH _______________________________________________ directfb-dev mailing list directfb-dev@directfb.org http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev _______________________________________________ directfb-dev mailing list directfb-dev@directfb.org http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev
