From: Thomas Gleixner tglx@linutronix.de
commit 862ee699fefe1e6d6f2c1518395f0b999b8beb15 upstream.
The console part of sisusbvga is broken vs. printk(). It uses in_atomic() to detect contexts in which it cannot sleep despite the big fat comment in preempt.h which says: Do not use in_atomic() in driver code.
in_atomic() does not work on kernels with CONFIG_PREEMPT_COUNT=n which means that spin/rw_lock held regions are not detected by it.
There is no way to make this work by handing context information through to the driver and this only can be solved once the core printk infrastructure supports sleepable console drivers.
Make it depend on BROKEN for now.
Fixes: 1bbb4f2035d9 ("[PATCH] USB: sisusb[vga] update") Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Thomas Winischhofer thomas@winischhofer.net Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201019101109.603244207@linutronix.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/misc/sisusbvga/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/usb/misc/sisusbvga/Kconfig +++ b/drivers/usb/misc/sisusbvga/Kconfig @@ -16,7 +16,7 @@ config USB_SISUSBVGA
config USB_SISUSBVGA_CON bool "Text console and mode switching support" if USB_SISUSBVGA - depends on VT + depends on VT && BROKEN select FONT_8x16 help Say Y here if you want a VGA text console via the USB dongle or