From: Nikola Pavlica <pavlica.nik...@gmail.com> Because some VMs in QEMU can get GPU virtualization (using technologies such as iGVT-g, as mentioned previously), they could produce a video output that had a higher display refresh rate than of what the GTK display was displaying. (fxp. Playing a video game inside of a Windows VM at 60 Hz, while the output stood locked at 33 Hz because of defaults set in include/ui/console.h)
Since QEMU does indeed have internal systems for determining frame times as defined in ui/console.c. The code checks for a variable called update_interval that it later uses for time calculation. This variable, however, isn't defined anywhere in ui/gtk.c and instead ui/console.c just sets it to GUI_REFRESH_INTERVAL_DEFAULT which is 30 update_interval represents the number of milliseconds per display refresh, and by doing some math we get that 1000/30 = 33.33... Hz This creates the mentioned problem and what this patch does is that it checks for the display refresh rate reported by GTK itself (we can take this as a safe value) and just converts it back to a number of milliseconds per display refresh. Signed-off-by: Nikola Pavlica <pavlica.nik...@gmail.com> --- include/ui/gtk.h | 2 ++ ui/gtk.c | 10 ++++++++++ 2 files changed, 12 insertions(+) diff --git a/include/ui/gtk.h b/include/ui/gtk.h index d9eedad976..d1b230848a 100644 --- a/include/ui/gtk.h +++ b/include/ui/gtk.h @@ -28,6 +28,8 @@ #include "ui/egl-context.h" #endif +#define MILLISEC_PER_SEC 1000000 + typedef struct GtkDisplayState GtkDisplayState; typedef struct VirtualGfxConsole { diff --git a/ui/gtk.c b/ui/gtk.c index 692ccc7bbb..eb0efc70ee 100644 --- a/ui/gtk.c +++ b/ui/gtk.c @@ -1966,6 +1966,10 @@ static GSList *gd_vc_gfx_init(GtkDisplayState *s, VirtualConsole *vc, GSList *group, GtkWidget *view_menu) { bool zoom_to_fit = false; + int refresh_rate_millihz; + GdkDisplay *dpy = gtk_widget_get_display(s->window); + GdkWindow *win = gtk_widget_get_window(s->window); + GdkMonitor *monitor = gdk_display_get_monitor_at_window(dpy, win); vc->label = qemu_console_get_label(con); vc->s = s; @@ -2026,6 +2030,12 @@ static GSList *gd_vc_gfx_init(GtkDisplayState *s, VirtualConsole *vc, vc->gfx.kbd = qkbd_state_init(con); vc->gfx.dcl.con = con; + + refresh_rate_millihz = gdk_monitor_get_refresh_rate(monitor); + if (refresh_rate_millihz) { + vc->gfx.dcl.update_interval = MILLISEC_PER_SEC / refresh_rate_millihz; + } + register_displaychangelistener(&vc->gfx.dcl); gd_connect_vc_gfx_signals(vc); -- 2.24.1