On Wed, Dec 11, 2019 at 11:26:17AM +0000, Ard Biesheuvel wrote: > On Tue, 10 Dec 2019 at 21:05, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote: > > Thanks. Another q -- I tried out the earlycon=efifb, and it seems like > > it gets disabled (without keep_bootcon) as soon as dummycon takes over, > > which is well before the real console. > > > > DUMMY_CONSOLE is defined as > > depends on VGA_CONSOLE!=y || SGI_NEWPORT_CONSOLE!=y > > default y > > > > so it seems like it will pretty much always be enabled, as it doesn't > > seem likely that VGA_CONSOLE=y and SGI_NEWPORT_CONSOLE=y would ever be > > true simultaneously. > > > > Am I missing something or is this the way it's supposed to work? So > > keep_bootcon seems almost necessary with the EFI boot console? Would a > > patch to not disable boot console when dummycon is initialized, but wait > > for a real console, be useful? > > > > Well spotted! > > I have traced this down to [0] which combined various arch specific > definitions into one, and obviously chose the wrong boolean operator > for combining the conditions. > > Patches welcome. > > > [0] https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/drivers/video/console/Kconfig?id=31d2a7d36d6989c714b792ec00358ada24c039e7 Thanks! I was a little mistaken about what actually disables it though, it seems to be when vt_console_driver gets registered, and at that point the vt is still using dummy_con. I had thought dummy_con itself was a console driver.
