[Bug 732326] v4l2: slow UVC webcam startup due to excessive S_FMT

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=732326
  GStreamer | gst-plugins-good | git

Daniel Drake <dan> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
 Attachment #279374|0                           |1
        is obsolete|                            |

--- Comment #10 from Daniel Drake <dan at reactivated.net> 2014-07-01 12:22:09 UTC ---
Created an attachment (id=279672)
 View: https://bugzilla.gnome.org/attachment.cgi?id=279672
 Review: https://bugzilla.gnome.org/review?bug=732326&attachment=279672

v4l2object: drop workaround for misbehaving TRY_FMT

This workaround from 2011 was causing 25 S_FMT ioctls to be sent
to my UVC webcam from under gst_v4l2_object_get_caps as it probes
all the formats. In total, this adds up to about 5 seconds of
execution time, or a 10 second delay while starting up cheese.

These ioctls come from a workaround from 2011 where TRY_FMT might
make changes to hardware settings, so S_FMT was used to restore
the original config:
https://bugzilla.gnome.org/show_bug.cgi?id=649067

The driver bug is assumed fixed, so we will drop this slow
workaround for the common case. However, there is still a fallback on
S_FMT for drivers that don't support TRY_FMT, and if we do hit that
codepath, restoring the original format (just once, at end of probe) is
a good idea.

-- 
Configure bugmail: https://bugzilla.gnome.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the QA contact for the bug.
You are the assignee for the bug.