* Use XResetScreenSaver() instead of disabling screensaver entirely.
Full discussion summary from Erik on the SDL mailing list:
Current behaviour
=================
SDL changes the user's display power management settings without
permission from the user and without telling the user.
The interface that it uses to do so is DPMSDisable/DPMSEnable, which
should only ever be used by configuration utilities like KControl, never
by normal application programs, let alone by the libraries that they
use. Using an interface that is not at all intended for what SDL tries
to achieve means that it will not work as it should. Firstly, the power
management is completely disabled during the whole lifetime of the SDL
program, not only when it should be. Secondly, it makes SDL
non-reentrant, meaning that things will break when multiple SDL programs
are clients of the same X server simultaneously. Thirdly, no cleanup
mechanism ensures that the setting is restored if the client does not do
that (for example if it crashes).
In addition to that, this interface is broken on xorg,
[http://bugs.freedesktop.org/show_bug.cgi?id=13962], so what SDL tries
to do does not work at all on that implementation of the X Window
System. (The reason that the DPMSEnable works in KControl is that it
calls DPMSSetTimeout immediately after,
[http://websvn.kde.org/tags/KDE/3.5.9/kdebase/kcontrol/energy/energy.cpp?annotate=774532#l343]).
The problems that the current behaviour causes
==============================================
1. Information leak. When the user is away, someone might see what the
user has on the display when the user counts on the screensaver
preventing this. This does not even require physical access to the
workstation, it is enough to see it from a distance.
2. Draining battery. An SDL program that runs on a laptop will quickly
drain the battery while the user is away. The system will soon shut down
and require recharging before being usable again, while it should in
fact have consumed very little energy if the user's settings would have
been obeyed.
3. Wasting energy. Even if battery issues are not considered, energy as
such is wasted.
4. Display wear. The display may be worn out.
The problems that the current behaviour tries to solve
======================================================
1. Preventing screensaver while playing movies.
Many SDL applications are media players. They have reasons to prevent
screensavers from being activated while a movie is being played. When a
user clicks on the play button it can be interpreted as saying "play
this movie, but do not turn off the display while playing it, because I
will watch it even though I do not interact with the system".
2. Preventing screensaver when some input bypasses X.
Sometimes SDL uses input from another source than the X server, so
that the X server is bypassed. This obviously breaks the screensaver
handling. SDL tries to work around that.
3. Preventing screensaver when all input bypasses X.
There is something called Direct Graphics Access mode, where a
program takes control of both the display and the input devices from the
X server. This obviously means that the X server can not handle the
screensaver alone, since screensaver handling depends on input handling.
SDL does not do what it should to help the X server to handle the
screensaver. Nor does SDL take care of screeensaver handling itself. SDL
simply disables the screensaver completely.
How the problems should be solved
=================================
The correct way for an application program to prevent the screensaver
under X is to call XResetScreenSaver. This was recently discovered and
implemented by the mplayer developers,
[http://svn.mplayerhq.hu/mplayer?view=rev&revision=25637]. SDL needs to
wrap this in an API call (SDL_ResetScreenSaver) and implement it for the
other video targets (if they do not have a corresponding call, SDL
should do what it takes on that particular target, for example sending
fake key events).
1. When a movie is played, the player should reset the screensaver when
the animation is advanced to a new frame. The same applies to anything
similar, like slideshows.
2. When the X server is handling input, it must handle all input
(keyboards, mice, gamepads, ...). This is necessary, not only to be able
to handle the screensaver, but also so that it can send the events to
the correct (the currently active) client. If there is an input device
that the X server can not handle for some reason (such as lack of Plug
and Play capability), the program that handles the device as a
workaround must simulate what would happen if the X server would have
handled the device, by calling XResetScreenSaver when input is received
from the device.
3. When the X server is not handling the input, it depends on the
program that does to call XResetScreenSaver whenever an input event
occurs. Alternatively the program must handle the screensaver countdown
internally and call XActivateScreenSaver.
--HG--
branch : SDL-1.2
From: Marcus von Appen
To: sdl@lists.libsdl.org
Subject: [SDL] [Patch] SDL-1.2 SDL_revcpy() asm patch for the cld flag
Hi,
as reported through the FreeBSD bug tracking system in SDL 1.2.13 (and
in the 1.2 branch, if I see that correctly) the SDL_revcpy() macro sets
the direction flag (std), but does not clear it afterwards (cld), which
is wrong according to the GCC and SYS V specs. This can cause some
weird side effects, which in turn can lead to memory corruption.
You can read the full report with a detailed description and test
program at http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/120052
Attached is the submitted patch, which fixes the issue.
Regards
Marcus
--HG--
branch : SDL-1.2
From: Christopher GAUTIER <krys via.ecp.fr>
To: sdl@lists.libsdl.org
Subject: [SDL] SDL_INPUT_LINUXEV vs SDL_JOYSTICK_LINUXEVHello all,
There seems to be a slight inconsistency between the SDL_INPUT_LINUXEV
define (used in src/joystick/linux/), and SDL_JOYSTICK_LINUXEV defined
in include/SDL_config.h.
SDL_JOYSTICK_LINUXEV is never used, and SDL_INPUT_LINUXEV is not
mentioned in SDL_config.h.in (though set by the ./configure script).
This has the unfortunate effect of breaking the joystick detection on linux
boxes where /dev/input/event* is defined, but not /dev/(input/)?js*.
Trivial patch included.
Cheers.
--HG--
branch : SDL-1.2
processor they ship (and thus, it's likely to beat our code on PowerPC and
Intel and whatever variants or new archs show up later).
--HG--
branch : SDL-1.2
Date: Mon, 26 Mar 2007 23:22:45 +0100
To: "A list for developers using the SDL library. \(includes SDL-announce\)" <sdl@lists.libsdl.org>
Subject: [SDL] SDL_config_macosx.h: MAC_OS_X_VERSION_MIN_REQUIRED
Hi,
I just compiled my SDL application on Mac OS X with -Wundef and it
threw a number of errors. Of note was:
SDL_config_macosx.h: 34
warning: "MAC_OS_X_VERSION_MIN_REQUIRED" is not defined
Line 34 is:
#if ( (MAC_OS_X_VERSION_MIN_REQUIRED >= 1030) || (!defined (__POWERPC__)) )
Now according to this mailing on the Apple developer lists:
http://lists.apple.com/archives/Xcode-users/2005/May/msg00602.html
that particular #define was removed from the gcc compiler defaults
and AvailabilityMacros.h (/usr/include/AvailabilityMacros.h) should
be pulled in directly instead.
Would someone closer to the Mac OS X version of SDL be willing to
make that change please? Thanks.
Laurence Passmore
Homeworld SDL @ www.homeworldsdl.org
--HG--
branch : SDL-1.2
since a memory page's size may vary on various architectures and kernel
configurations.
Will use getpagesize() if it exists, the PAGE_SIZE #define from older kernels
if that doesn't, and #error out if that's not there either...but it's
probably 4096 in that case. We may revisit this.
Fixes Bugzilla #392.
--HG--
branch : SDL-1.2
Added DirectInput joystick code, contributed by Glenn Maynard.
This fixes a problem with the Windows Multimedia joystick driver
not showing all 6 axes on a GameCube controller converter, which
was donated by Jacob Kolding.
