gma500_gfx: Avoid inserting gma500_gfx module for certain devices
The gma500_gfx driver will match certain devices on which it causes incorrect functionality,
we want to avoid inserting this module, basicallly blacklist it for specific hardware,
but still allow it to work on other hardware by default; usually when we have an already working system,
using udev rules would do the job, but since we are building it, it is impossible to blacklist
a driver when a certain udev rule matches, since rootfs isn't writeable at this point during boot time,
the solution is to use modprobe install, which runs a certain command instead of inserting a matching module,
this command needs to insert the module manually afterwards and have a flag --ignore-install
so it doesnt create an infinite loop executing itself everytime it wants to insert the module,
busybox's modprobe doesn't provide this functionality, so a small hack had to be used to avoid
the infite loop instead.
(From meta-yocto rev: 70c143767a8b63921e668a62ac463b3a6b8c6132)
Signed-off-by: Alejandro Hernandez <alejandro.hernandez@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
2015-11-09 16:11:57 +00:00
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#!/bin/sh
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# Check for devices we wish to avoid gma500_gfx for
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DEVICES="0x8119 0x4108"
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2016-02-16 03:07:29 +00:00
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# Checked flag to avoid infinite modprobe
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echo "gma500_gfx_checked" >> /dev/kmsg;
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gma500_gfx: Avoid inserting gma500_gfx module for certain devices
The gma500_gfx driver will match certain devices on which it causes incorrect functionality,
we want to avoid inserting this module, basicallly blacklist it for specific hardware,
but still allow it to work on other hardware by default; usually when we have an already working system,
using udev rules would do the job, but since we are building it, it is impossible to blacklist
a driver when a certain udev rule matches, since rootfs isn't writeable at this point during boot time,
the solution is to use modprobe install, which runs a certain command instead of inserting a matching module,
this command needs to insert the module manually afterwards and have a flag --ignore-install
so it doesnt create an infinite loop executing itself everytime it wants to insert the module,
busybox's modprobe doesn't provide this functionality, so a small hack had to be used to avoid
the infite loop instead.
(From meta-yocto rev: 70c143767a8b63921e668a62ac463b3a6b8c6132)
Signed-off-by: Alejandro Hernandez <alejandro.hernandez@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
2015-11-09 16:11:57 +00:00
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for DEVICE in $DEVICES; do
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if udevadm trigger --subsystem-match=pci --verbose --attr-match=device=$DEVICE | grep "pci" >> /dev/null ; then
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echo "Found $DEVICE, avoiding gma500_gfx module" >> /dev/kmsg;
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exit 0
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fi
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done
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exit 1
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