After upgrading GTK+ 4 on Hương Tràm, Megapixels now can occasionally start on Sxmo. Since the following patch seems to fix the crash, I suspect it is due to a race condition.
diff --git a/src/main.c b/src/main.c
index b096e8e..67ba5b5 100644
--- a/src/main.c
+++ b/src/main.c
@@ -2,6 +2,7 @@
#include <errno.h>
#include <fcntl.h>
+#include <unistd.h>
#include <linux/videodev2.h>
#include <linux/media.h>
#include <linux/v4l2-subdev.h>
@@ -914,6 +915,7 @@ activate(GtkApplication *app, gpointer data)
update_screen_rotation(conn);
mp_io_pipeline_start();
+ sleep(1);
gtk_application_add_window(app, GTK_WINDOW(window));
gtk_widget_show(window);
Edit: This was last night. The patch isn't working for me any more )-;
So is the GTK4 issue actually fixed? Do we know what the issue was? Right now we are doing nothing more than playing bug tracker ping pong between Megapixels and SXMO.
#51 was fixed, I don't have any insight though. Megapixels now can occasionally starts on my ALARM with Sxmo, but in most of the cases the window is not initialized (i.e. there's a frame with the content of the element underneath), which response to close event but
megapixelsdoes not die with it (I still need to^Cat it).
#51 was only closed because it is believed to be a bug in SXMO. Over at SXMO it was closed because they thought it had been solved elsewhere. So now we have a "resolved: not our bug" in both bug trackers and no actual solution. Someone with knowledge of GTK at their hands or a lot of time would need to have a look at what the actual issue is.
So now we have [...] no actual solution
There is: Megapixels is working on Sxmo on ALARM. Since this only started to happen after an GTK+ 4 upgrade, my bet would be on the GTK+ 4 version. On Arch Linux it is currently 4.2.1-1 while on Alpine Linux it is 4.2.0-r0.
I agree that for the race condition,
Someone with knowledge [...] at their hands or a lot of time would need to have a look at what the actual issue is.
Well, 4.2.1 sure helped in a sense. Now I get a different error on every startup. In one case Megapixels even showed the preview image only to crash on taking a photo with process_pipeline.c: process_image: 593 I'm struggling a bit with redirecting both stdout and stderr in ash, so I don't have proper logs yet.
One issue seems to be that Megapixels asks over DBUS for a DisplayConfig. org.freedesktop.DBus.Error.NameHasNoOwner: Name "org.gnome.Mutter.DisplayConfig" From what I could gather that is provided by the Gnome Settings Daemon, which of course is not running on SXMO.
This is more likely a regular failure than the root cause of this issue.
Also interesting, on Phosh vs SXMO Megapixels initialises:
OpenGL ES 2.0
OpenGL 2.1
I have found further evidence that it is indeed a race condition. Megapixels starts up reliably for me through X-Forwarding.
- Enable X forwarding on the PinePhone.
- Connect using 'ssh -X -Y -C'.
- Uninstall megapixels-gtk3-0.16.1-r0 and install megapixels-1.0.1-r0 (in that order since the packages are not conflicting and would overwrite files).
- Start megapixels and see it work (with abysmal framerate, but still).
$ GDK_SCALE=2 megapixels Renderdoc not found Found config file at /usr/share/megapixels/config/pine64,pinephone-1.2.ini Adding camera rear from config Adding camera front from config debug1: client_input_channel_open: ctype x11 rchan 3 win 65536 max 16384 debug1: client_request_x11: request from ::1 37554 debug1: channel 1: new [x11] debug1: confirm x11 (megapixels:10848): GLib-GIO-CRITICAL **: 22:16:55.715: g_dbus_connection_signal_subscribe: assertion 'G_IS_DBUS_CONNECTION (connection)' failed (megapixels:10848): GLib-GIO-CRITICAL **: 22:16:55.715: g_dbus_connection_call_internal: assertion 'G_IS_DBUS_CONNECTION (connection)' failed Found postprocessor script at /usr/share/megapixels/postprocess.sh Initialized OpenGL 3.1 (megapixels:10848): Gtk-CRITICAL **: 22:16:59.041: Unable to connect to the accessibility bus at 'unix:path=/tmp/dbus-JC3XqPgPFe,guid=a2258a4fe58728b5db7b9eb760e48c50': Could not connect: No such file or directory Gdk-Message: 22:16:59.135: Failed to get file transfer portal: Failed to execute child process “dbus-launch” (No such file or directory)
Probably unrelated but this error comes up regularly while running megapixels this way, but it doesn't have any obvious adverse effect.
WARNING: decoder/databar.c:1248: _zbar_decode_databar: Assertion "seg->finder >= 0" failed. i=31 f=-1(010) part=0
Issue now tracked here: https://gitlab.com/postmarketOS/megapixels/-/issues/14