vt: call driver's postswitch when panicking on ttyv0

[val_packett.cool]

Summary

In vt_kms, the postswitch callback restores fbdev mode when panicking or entering the debugger. This ensures that even when a graphical application was running on the first tty, simple framebuffer mode would be restored and the panic would be visible instead of the frozen GUI. But vt wouldn't call the postswitch callback when we're already on the first tty, so running a GUI on it would prevent you from reading any panics.

Test Plan

sysctl debug.kdb.panic=1 when running a graphical session on the first tty.

[val_packett.cool]

ping. someone please commit?

[tsoome]

In D29961#721194, @greg_unrelenting.technology wrote:

ping. someone please commit?

Could you mail me git format-patch?

[val_packett.cool]

In D29961#721288, @tsoome wrote:

In D29961#721194, @greg_unrelenting.technology wrote:

ping. someone please commit?

Could you mail me git format-patch?

Done (sent to the freebsd.org address). Also updated it here, though "Download Raw Diff" still extracts a small diff anyway :/ Seems like only arc can apply patches with the message and everything from phab.

[tsoome]

In D29961#721453, @greg_unrelenting.technology wrote:

In D29961#721288, @tsoome wrote:

In D29961#721194, @greg_unrelenting.technology wrote:

ping. someone please commit?

Could you mail me git format-patch?

Done (sent to the freebsd.org address). Also updated it here, though "Download Raw Diff" still extracts a small diff anyway :/ Seems like only arc can apply patches with the message and everything from phab.

oh, sorry, I have missed this some time.

could you mail it to [e-mail] - I havent got the file from freebsd.org.. the plain mails are coming through, probably is blocking the attachments.