On Sat, Jan 19, 2013 at 01:46:15PM -0500, Alan Stern wrote: > On Sat, 19 Jan 2013, Aaron Lu wrote: > > > > What happens if you're not running a desktop graphical environment, so > > > gvfs doesn't mount the disc? Basically, I'm worried that the drive may > > > remain suspended after sr_open() returns. > > > > Tried on my notebook with a normal ODD, using mplayer under console > > mode, no GUI environment running, works fine. > > > > The usage count will be incremented by the app, and get decreased > > only when it exits. So the ODD will not be in runtime suspended state > > when the app is running. > > You missed my point. What happens when sr_open() gets called? It > doesn't try to resume the device. Will we run into trouble then?
Oh yes, you mean the cdo->open gets called without going through sr's block interface. I just checked the code, it looks to me the cdrom interface code is the code common to cdrom functionality, to be used by various underlying block drivers like sr, ide-cd, etc. All the code cdrom.c has provided requires a cdi parameter, which can only be provided by the underlying block driver, so I don't think those cdrom_device_ops functions will be called without going through the block drivers' interface. But the functions defined in block_device_operations by sr can be called by other kernel components as long as they have access to the gendisk structure of the block device, so I'll add get/sync pair to all those functions(i.e. sr_block_revalidate_disk, sr_block_ioctl in addition to the open/release/check_events calls). > > > > What happens if you use a program other than rhythmbox? There are (or > > > used to be) programs which would issue the PLAY AUDIO command and then > > > exit. The drive would continue playing even while the device file was > > > > Then we indeed have a problem. But I didn't find any such app in > > Fedora's repo or by searching the internet. > > http://rpm.pbone.net/index.php3/stat/4/idpl/2392183/dir/redhat_5.x/com/cdp-0.33-10.i386.rpm.html > > > > closed. Do we want to drop support for that kind of behavior? > > > > I don't think we should drop such support. > > And the safest way to avoid such break is we refine the suspend > > condition for ODD, and using what ZPODD defined condition isn't that > > bad to me: > > - for tray type, no media inside and tray close; > > - for slot type, no media inside. > > While whether tray is closed or not may not be that important, but at > > least we should make sure there is no media inside. > > > > Thoughts? > > That sounds reasonable to me, at least as a first step. If people want > their CD drive to suspend, they can eject the disc. I'm gonna add the cd->media_present check in sr's runtime suspend callback, if sr thinks there is media inside, suspend will not proceed. Thanks, Aaron -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
