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862ee699fe
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>
49 lines
1.5 KiB
Plaintext
49 lines
1.5 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
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config USB_SISUSBVGA
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tristate "USB 2.0 SVGA dongle support (Net2280/SiS315)"
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depends on (USB_MUSB_HDRC || USB_EHCI_HCD)
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select FONT_SUPPORT if USB_SISUSBVGA_CON
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help
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Say Y here if you intend to attach a USB2VGA dongle based on a
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Net2280 and a SiS315 chip.
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Note that this device requires a USB 2.0 host controller. It will not
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work with USB 1.x controllers.
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To compile this driver as a module, choose M here; the module will be
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called sisusbvga. If unsure, say N.
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config USB_SISUSBVGA_CON
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bool "Text console and mode switching support" if USB_SISUSBVGA
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depends on VT && BROKEN
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select FONT_8x16
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help
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Say Y here if you want a VGA text console via the USB dongle or
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want to support userland applications that utilize the driver's
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display mode switching capabilities.
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Note that this console supports VGA/EGA text mode only.
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By default, the console part of the driver will not kick in when
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the driver is initialized. If you want the driver to take over
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one or more of the consoles, you need to specify the number of
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the first and last consoles (starting at 1) as driver parameters.
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For example, if the driver is compiled as a module:
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modprobe sisusbvga first=1 last=5
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If you use hotplug, add this to your modutils config files with
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the "options" keyword, such as eg.
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options sisusbvga first=1 last=5
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If the driver is compiled into the kernel image, the parameters
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must be given in the kernel command like, such as
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sisusbvga.first=1 sisusbvga.last=5
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