Mark Lord wrote:
Sebastian Kemper wrote:
Hi Alan!
On Tue, Nov 13, 2007 at 09:22:30PM +0000, Alan Cox wrote:
It isn't a known issue, and it suprises me as SG_IO basically passes
commands through to the drive. We don't support speed change via
xfermode
setting but GPCMD_SET_STREAMING sohuld behave.
Do you have a simple code example that shows the problem ?
http://svn.mplayerhq.hu/mplayer/trunk/stream/stream_dvd.c?view=markup
..
That code is riddled with bugs, by the way.
It fails to close/clean-up on just about every exit path.
But apart from that, it does appear to issue the command.
Another way to the same thing is with "hdparm -E",
which contrary to my earlier posting actually does
seem to work already with libata.
See dvd_set_speed(). The drive I'm using is an Optiarc DVD RW AD-7170A.
With the "old" ATA driver dvd_set_speed() works, with libata it doesn't.
..
Can you define "doesn't work" for me?
How can I test this to see if it works one way or another ?
The command issue (ioctl) is not returning -1.
..
Ahh.. got it. The host_status returned (not checked by that code) was 7,
which means "host error".
In this case, that's because the cmd_len is (16), which is too large for ATAPI.
It needs to be changed to (12) instead.
So this line: sghdr.cmd_len = 12;
The code (apart from totally mishandling any kinds of errors) works after that.
-ml
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