Re: dbus-call-method blocks for a long time

[Michael Albinus <michael.albinus@gmx.de>]

Lluís <xscript@gmx.net> writes:

Hi Lluís,

> I'm not quite sure if this is an issue with `notifications' but this piece of
> code is getting my emacs completely frozen for a while every time it calls
> `notifications-notify' (sometimes not even C-g gets out of it):
>
> #v+
> (defun gnus-notifications-notify (from subject photo-file)
>   "Send a notification about a new mail.
> Return a notification id if any, or t on success."
>   (if (fboundp 'notifications-notify)
>       (gnus-funcall-no-warning
>        'notifications-notify
>        :title from
>        :body subject
>        :actions '("read" "Read")
>        :on-action 'gnus-notifications-action
>        :app-icon (gnus-funcall-no-warning
> 		  'image-search-load-path "gnus/gnus.png")
>        :app-name "Gnus"
>        :category "email.arrived"
>        :timeout gnus-notifications-timeout
>        :image-path photo-file)
>     (message "New message from %s: %s" from subject)
>     ;; Don't return an id
>     t))
> #v-

`notifications-notify' doesn't set a timeout for `dbus-call-method' and
`dbus-get-name-owner' (maybe they should). Therefore, the default
timeout of D-Bus is used, which is 25,000 milliseconds. And indeed, both
functions wait exactly this time:

> dbus-call-method                      6           150.09408380  25.015680634
> dbus-get-name-owner                   3           75.051887114  25.017295704

> Looks strange to me that `dbus-call-method' takes so long while the notification
> message appears immediately on my screen.

This is really strange. When the notification appears on your desktop,
`dbus-call-method' has been applied successfully. But Emacs does not
receive the return message of that call.

> Does this sound like a problem in Emacs's DBus immplementation, or should I
> rather look in another direction?

Do you have some special settings wrt D-Bus? For example, do you play
with $DBUS_SESSION_BUS_ADDRESS, or do you use a private D-Bus
connection?

Could you trace D-Bus events in a shell outside Emacs, by calling
"dbus-monitor"? In parallel, you might also trace D-Bus events inside
Emacs by setting `dbus-debug' to `t'.

> Thanks,
>   Lluis

Best regards, Michael.