On Fri, Jan 13, 2017 at 09:07:57PM +0100, Manuel Schölling wrote: > Add a scrollback buffers for each VGA console. The benefit is that > the scrollback history is not flushed when switching between consoles > but is persistent. > The buffers are allocated on demand when a new console is opened. > > This breaks tools like clear_console that rely on flushing the > scrollback history by switching back and forth between consoles > which is why this feature is disabled by default. > Use the escape sequence \e[3J instead for flushing the buffer. > > Signed-off-by: Manuel Schölling <[email protected]> > Reviewed-by: Andrey Utkin <[email protected]> > Tested-by: Andrey Utkin <[email protected]> > Tested-by: Adam Borowski <[email protected]> > --- > drivers/video/console/Kconfig | 25 +++++++- > drivers/video/console/vgacon.c | 142 > ++++++++++++++++++++++++++--------------- > 2 files changed, 111 insertions(+), 56 deletions(-) > > diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig > index c3f1fb9ee820..f500e58f7636 100644 > --- a/drivers/video/console/Kconfig > +++ b/drivers/video/console/Kconfig > @@ -43,9 +43,28 @@ config VGACON_SOFT_SCROLLBACK_SIZE > range 1 1024 > default "64" > help > - Enter the amount of System RAM to allocate for the scrollback > - buffer. Each 64KB will give you approximately 16 80x25 > - screenfuls of scrollback buffer > + Enter the amount of System RAM to allocate for scrollback > + buffers of VGA consoles. Each 64KB will give you approximately > + 16 80x25 screenfuls of scrollback buffer. > + > +config VGACON_SOFT_SCROLLBACK_PERSISTENT > + bool "Persistent Scrollback History for each console" > + depends on VGACON_SOFT_SCROLLBACK > + default n > + help > + Say Y here if the scrollback history should persist when switching > + between consoles. Otherwise, the scrollback history will be flushed > + each time the console is switched. > + > + This feature might break your tool of choice to flush the scrollback > + buffer, e.g. clear(1) will work fine but Debian's clear_console(1) > + will be broken, which might cause security issues. > + You can use the escape sequence \e[3J instead if this feature is > + activated.
This issue is the one that makes me the most worried. Why doesn't clear_console() work anymore? Why doesn't it use \e[3J ? thanks, greg k-h
