On Wed, 23 Jun 2010 12:56:05 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Wed, 23 Jun 2010 13:12:59 +1000 > Dave Airlie <airlied@xxxxxxxxx> wrote: > > > Jesse's initial patch commit said: > > > > "At panic time (i.e. when oops_in_progress is set) we should try a bit > > harder to update the screen and make sure output gets to the VT, since > > some drivers are capable of flipping back to it. > > > > So make sure we try to unblank and update the display if called from a > > panic context." > > > > I've enhanced this to add a flag to the vc that console layer can set > > to indicate they want this behaviour to occur. This also adds support > > to fbcon for that flag and adds an fb flag for drivers to indicate > > they want to use the support. It enables this for KMS drivers. > > Interesting. Getting real oops traces from machines running X will > make Rusty happy, and that's what we're all here for. > > How well does this all work? How reliable is it? What's the success rate? > > > > What's the downside here? After all, not all oopses are catastrophic - > sometimes the machine will go blurt and keep running so the user can > take a look in the logs then perform an orderly reboot, etc. As I > understand it, those non-catastrophic oopses will now flip the machine > from X and into the vt display, yes? Can the user get it back to X > mode? No, we'll only flip from the panic notifier chain. However if oops_in_progress is set (as it is whenever bust_spinlocks(1) is called, i.e. from panic() and oops_begin()) we'll try to print into the fbcon buffer. In the oops case this should still be safe since the buffer is pinned, at least in the KMS world. > Worse, there's also a risk that doing all this new work within the > oopsing context will screw the machine up, so the user will be > _deprived_ of an oops report which he otherwise would have been able to > get from the logs. This is particularly the case when it's the DRI > stuff which oopsed, which is not exactly an uncommon occurrence lately ;) > > Oh well, the best way to tell is to ship-it-and-see. To avoid the oops part (which as I said should still be safe) we could add a new panic_in_progress flag, that would make sure things were no worse than they are currently. -- Jesse Barnes, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
