I found the mplayer just show a blue screen on FCore 7 system with upstream kernel 2.6.25-rc1/rc3.
But when I add "-vo x11" parameters for mplayer:
#mplayer -vo x11 /dev/dvd 
to player the same video, the screen goes back. So I raise this issue here. 
If I change to 2.6.25-rc2 kernel the problem disappear. 

==================================
#lspci
...
08:01.0 VGA compatible controller: ATI Technologies Inc ES1000 (rev 02)
...
#mplayer /dev/dvd
MPlayer 1.0rc1-4.1.2 (C) 2000-2006 MPlayer Team
CPU: Intel(R) Xeon(R) CPU           E5440  @ 2.83GHz (Family: 6, Model: 23, Stepping: 6)
CPUflags:  MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled for x86 CPU with extensions: MMX MMX2 SSE SSE2

Playing dvd://.
There are 2 titles on this DVD. 
There are 9 chapters in this DVD title.
There are 1 angles in this DVD title.
audio stream: 0 format: ac3 (stereo) language: en aid: 128.
number of audio channels on disk: 1.
subtitle ( sid ): 0 language: zh
subtitle ( sid ): 1 language: en
number of subtitles on disk: 2 
MPEG-PS file format detected.
VIDEO:  MPEG2  352x240  (aspect 2)  29.970 fps  1150.0 kbps (143.8 kbyte/s)
==========================================================================
Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough
VDec: vo config request - 352 x 240 (preferred colorspace: Mpeg PES)
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
The selected video_out device is incompatible with this codec.
Try adding the scale filter, e.g. -vf spp,scale instead of -vf spp.
VDecoder init failed :(
Opening video decoder: [libmpeg2] MPEG 1/2 Video decoder libmpeg2-v0.4.0b
Selected video codec: [mpeg12] vfm: libmpeg2 (MPEG-1 or 2 (libmpeg2))
Opening video decoder: [libmpeg2] MPEG 1/2 Video decoder libmpeg2-v0.4.0b
Selected video codec: [mpeg12] vfm: libmpeg2 (MPEG-1 or 2 (libmpeg2))
==========================================================================
==========================================================================
Opening audio decoder: [liba52] AC3 decoding with liba52
Using SSE optimized IMDCT transform
Using MMX optimized resampler
AUDIO: 48000 Hz, 2 ch, s16le, 96.0 kbit/6.25% (ratio: 12000->192000)
Selected audio codec: [a52] afm: liba52 (AC3-liba52)
==========================================================================
[AO OSS] audio_setup: Can't open audio device /dev/dsp: Permission denied
alsa-lib: confmisc.c:769:(parse_card) cannot find card ''
alsa-lib: conf.c:3500:(_snd_config_evaluate) function snd_func_card_driver returned error: No such device
alsa-lib: confmisc.c:392:(snd_func_concat) error evaluating strings
alsa-lib: conf.c:3500:(_snd_config_evaluate) function snd_func_concat returned error: No such device
alsa-lib: confmisc.c:1247:(snd_func_refer) error evaluating name
alsa-lib: conf.c:3500:(_snd_config_evaluate) function snd_func_refer returned error: No such device
alsa-lib: conf.c:3972:(snd_config_expand) Evaluate error: No such device
alsa-lib: pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM default
alsa-init: playback open error: No such device
[AO ESD] esd_open_sound failed: No such file or directory
[AO SDL] Samplerate: 48000Hz Channels: Stereo Format s16le
alsa-lib: confmisc.c:769:(parse_card) cannot find card ''
alsa-lib: conf.c:3500:(_snd_config_evaluate) function snd_func_card_driver returned error: No such device
alsa-lib: confmisc.c:392:(snd_func_concat) error evaluating strings
alsa-lib: conf.c:3500:(_snd_config_evaluate) function snd_func_concat returned error: No such device
alsa-lib: confmisc.c:1247:(snd_func_refer) error evaluating name
alsa-lib: conf.c:3500:(_snd_config_evaluate) function snd_func_refer returned error: No such device
alsa-lib: conf.c:3972:(snd_config_expand) Evaluate error: No such device
alsa-lib: pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM default
[AO SDL] Unable to open audio: No available audio device
Opening /dev/dvb/adapter0/audio0
DVB AUDIO DEVICE: No such file or directory
AO: [null] 48000Hz 2ch s16le (2 bytes per sample)
Starting playback...