vt(4): reset scrollback and cursor position after clearing history buffer
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Authored by jah on May 30 2020, 9:29 PM.

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emaste

Commits

rS361719: vt(4): reset scrollback and cursor position after clearing history buffer

Summary

r361601 implemented basic support for cleaing the console history buffer.
But after clearing the history buffer, it's not especially useful to be
able to scroll back through that buffer, or for the cursor position to
remain at (very likely) the bottom of the screen.

Diff Detail

Repository

rS FreeBSD src repository - subversion

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No Test Coverage

Build Status

Buildable 31402
Build 29025: arc lint + arc unit

Event Timeline

jah created this revision.May 30 2020, 9:29 PM

Herald added a subscriber: imp. · View Herald TranscriptMay 30 2020, 9:29 PM

Harbormaster completed remote builds in B31399: Diff 72462.May 30 2020, 9:29 PM

jah requested review of this revision.May 30 2020, 9:29 PM

jah added a reviewer: emaste.May 30 2020, 9:30 PM

jah added inline comments.May 30 2020, 11:56 PM

sys/kern/subr_terminal.c
494	This exposes a new issue: before, it was practically guaranteed that the cursor would be at the bottom of the screen, so the CLRHIST ioctl would be immediately followed by a scroll event that would invalidate the entire visible rect. Now that may no longer be the case: for example if you issue 'vidcontrol -C', then do a few things that don't fill the screen, then issue 'vidcontrol -C' again, some prior artifacts might still remain visible. Let me see if I can fix that...

Ensure the visible rect is invalidated on CONS_CLRHIST

Harbormaster completed remote builds in B31400: Diff 72465.May 31 2020, 12:28 AM

emaste accepted this revision.May 31 2020, 12:48 AM

emaste added inline comments.

sys/kern/subr_terminal.c
485	IMO it'd be fine to do `if (cmd == CONS_CLRHIST)` which neatly avoids the slightly confusing double `}` at the same indentation; we can deal with the awkwardness if we ever have a 2nd case to deal with. Yes, this is slightly inconsistent with the switch above.