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Bug 28486 - Mplayer - /dev/misc/rtc permissions change & sysctl.conf addition
Summary: Mplayer - /dev/misc/rtc permissions change & sysctl.conf addition
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: New packages (show other bugs)
Hardware: All Linux
: Lowest enhancement (vote)
Assignee: Gentoo's Team for Core System packages
Depends on:
Reported: 2003-09-11 19:59 UTC by Louis Rush
Modified: 2006-10-07 17:42 UTC (History)
4 users (show)

See Also:
Package list:
Runtime testing required: ---


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Description Louis Rush 2003-09-11 19:59:58 UTC
After seeing a few posts in the forums asking about the /dev/rtc error that 
mplayer gives if it cannot use RTC hardware timing, It occured to me that this 
issue could be fixed in the ebuild. 

I am not a coder. I know I am not fully qualified to impliment this change, or 
evaluate the implications & repercussions if it was implimented. 

That being said, I think it would help out some folks if the ebuild for MPlayer 
checked the permissions on /dev/rtc & /dev/misc/rtc for read rights for non-
root users, and adjusted them accordingly (say 644). 

It is also IMO benificial to adjust /etc/sysctl.conf with the entry Code: 
dev.rtc.max-user-freq = 1024 

so that hardware timings are set just the way Arpi (or whoever at MPlayer.hq) 
thinks they should be set for multimedia playback, and end users can benifit 
from using hardware timing. Not to mention removing one more warning a person 
may see when running software.
Comment 1 Martin Schlemmer (RETIRED) gentoo-dev 2003-09-13 13:54:56 UTC
Or the admin could add an 'rtc' group, do a 'chmod g+r /dev/misc/rtc', and
add whoever should have read access to the 'rtc' group ?  I am no so sure
if this is an problem that should be handeled inside the ebuild, and anyhow,
most people would not like the sysctl.conf change without supervision ?

Any other ideas/comments/etc ?
Comment 2 Patrick Kursawe (RETIRED) gentoo-dev 2003-10-06 00:45:17 UTC
I don't think this should be handled in the ebuild silently. Maybe some hint
in the postinst function? Or put it into a "config" function and give a hint
in postinst?
Comment 3 John Mylchreest (RETIRED) gentoo-dev 2003-10-06 12:08:03 UTC
I feel we should have this changed in baselayout.
IE. add a group called rtc, change permissions as neccessary and then advise
in the mplayer postinst to add any regular users wanting to use mplayer should
be added to the rtc group.

I know I would find that group handy for other reasons.
Comment 4 Joe Tennies 2003-12-18 14:55:03 UTC
I think instead of creating an rtc group you should utilize current groups.  I personally set mine to root:bin 640.  I find this to be a much more reasonable permission.  People shouldn't have to add everyone that wants to use a video player (and its associated browser plugin) to a certain group.

Also, I think it's worth noting that the window manager if the permissions are not right (at least on my computer w/ metacity).
Comment 5 Kurt Lieber (RETIRED) gentoo-dev 2004-03-30 01:19:53 UTC
bug-cleaning.  removing security@ cc
Comment 6 Benjamin Judas (RETIRED) gentoo-dev 2004-08-25 01:24:22 UTC
Is this still an issue?
Comment 7 Will McQueen 2004-08-25 09:08:01 UTC
If you run >= udev-030, this should be fixed (along with the sysctl.conf change.)  The default gentoo permissions for /dev/misc/rtc is 0664 which should make the rtc readable for all users.  And the sysctl.conf change allows mplayer to read the rtc at the frequency it wants to.
Comment 8 Chris White (RETIRED) gentoo-dev 2004-11-09 11:50:33 UTC
Base-System team,

   Thoughts on this?  As johnm mentioned, there are probably a number of packages that could utilize such a group.  I can think of many video and sound apps myself.  I could do it in the MPlayer build, but I'd be more comfortable if it was a base-system created group.  Thanks ahead of time for any thoughts.
Comment 9 SpanKY gentoo-dev 2004-11-09 21:08:57 UTC
ntp could also use it i believe

can you give me examples to add to passwd / sysctl.conf ?
Comment 10 Diego Elio Pettenò (RETIRED) gentoo-dev 2005-03-21 00:39:54 UTC
/dev/rtc should not be a problem at the moment, as udev has it 664, and I don't think there's someone which needs to be allowed to write to that device.

About max-user-freq, I actually don't know what does that implies, but it's requested by tvtime, also. But this shouldn't be a mplayer bug anymore, it's something for baselayout, imho.
Comment 11 Chris White (RETIRED) gentoo-dev 2005-03-27 14:24:38 UTC
something like:

rtc::23: in /etc/group 

would probably do.  Note that I base the 23 off the fact that I don't see in 23 GID group unless it's something that's part of baselayout and I don't know about.


dev.rtc.max-user-freq = 1024

Should be added to /etc/sysctl.conf someplace.
Comment 12 Jan Brinkmann (RETIRED) gentoo-dev 2005-04-15 11:07:04 UTC
base-system, please review and close as invalid if you dont like the idea of adding this to the basesystem. thanks
Comment 13 SpanKY gentoo-dev 2005-04-24 17:17:47 UTC
gregkh: what's your opinion ?
Comment 14 Greg Kroah-Hartman (RETIRED) gentoo-dev 2005-04-24 21:53:19 UTC
Adding another group?  Fine with me, send me a patch for the udev rules if you decide to do this.
Comment 15 Sebastian Krämer 2006-09-27 09:11:24 UTC
Actually, I think this change isn't necessare (any more). The MPlayer team now propagates the usleep (or nanosleep?) timing since some benchmarks showed better performance while keeping accuracy.
I'm not sure though if this is already the case for pre8 (which is the oldest MPlayer in portage)..
Comment 16 SpanKY gentoo-dev 2006-10-07 17:42:59 UTC