On 5/20/26 05:31, Ethan Nelson-Moore wrote:
The mdacon driver supports using ISA MDA or Hercules-compatible display adapters as a secondary text console. This was commonly used in the 1990s and earlier for debugging software which took over the primary display. It is highly unlikely anyone is doing so nowadays because serial consoles and much better methods of debugging exist.The driver is not enabled by any defconfig, nor any of the dozens of distro configs collected at [1]. It has been relegated to VTs 13-16 since commit 0b9cf3aa6b1e ("mdacon messing up default vc's - set default to vc13-16 again") in Linux 2.6.27 (and before Linux 2.5.53 - see the link in the message of the above commit). The change in 2.6.27 was done because it was incorrectly detecting non-MDA adapters as MDA and taking over all VTs, rendering them unusable. Furthermore, vgacon supports using MDA/Hercules-compatible adapters as the primary text console, so any systems with only one of these adapters were already using vgacon and will not experience any loss in functionality from the removal of this driver. Given all of these factors, the mdacon driver is likely entirely unused. Remove it.
I've applied this patch to the fbdev git tree, since I also believe that there is no use case or user left (with Linux kernels >= 7.0), which uses the mdacon. If someone thinks we need to keep it, please speak up. Helge
[1] https://github.com/nyrahul/linux-kernel-configs/tree/f0bee86a135a0406ea427855f52702dd00d770f9 Signed-off-by: Ethan Nelson-Moore <[email protected]> --- .../admin-guide/kernel-parameters.txt | 5 - arch/alpha/kernel/io.c | 2 +- arch/powerpc/include/asm/vga.h | 4 +- drivers/tty/vt/vt.c | 3 - drivers/video/console/Kconfig | 15 - drivers/video/console/Makefile | 1 - drivers/video/console/mdacon.c | 566 ------------------ include/linux/console.h | 2 - include/linux/vt_buffer.h | 2 +- 9 files changed, 4 insertions(+), 596 deletions(-) delete mode 100644 drivers/video/console/mdacon.c
