Fear and loathing in FreeBSD 7.2 (AGP issues and fixes)
Paul B. Mahol
onemda at gmail.com
Sun May 17 00:55:43 UTC 2009
On 5/17/09, Paul B. Mahol <onemda at gmail.com> wrote:
> On 5/17/09, Bill Paul <wpaul at freebsd.org> wrote:
>>
>> So. I decided to test FreeBSD 7.2 on my Averatec AV1020 ED1 laptop. (It
>> currently has 6.0-RELEASE on it, and while it runs fine, I figured now
>> was a good time to update it.) I ran into two problems with it, and I
>> thought it would be a good idea to share how I resolved them, just in
>> case anyone else is foolish enough to follow in my tracks.
>>
>> The laptop has a RaLink RT2560 wireless chipset. The ral(4) driver
>> supports this chip out of the box, however that driver doesn't support
>> WPA2 Enterprise, which I need for work. To get around this, I use
>> the Windows NDIS driver with Project Evil. Unfortunately, the driver
>> that comes with the laptop (version 3.0.3.0000) is buggy, and will
>> trigger a kernel panic in certain conditions. It seems to have trouble
>> parsing information from certain newer kinds of devices, which causes
>> some of the code inside the driver binary to dereference a bogus pointer.
>>
>> This is not a problem with FreeBSD or Project Evil: I discovered that
>> the same driver blue-screens Windows XP as well (a testament to just
>> how closely Project Evil emulates Windows: it even emulates its crashes).
>> Luckily there is a slightly newer driver available that fixes this issue
>> (3.1.0.000), though I had to hunt a bit to find it. I put copies of
>> the .SYS and .INF at:
>>
>> http://www.freebsd.org/~wpaul/7_2_RELEASE/wifi
>>
>> The other problems I had were with graphics. The Averatec has an Intel
>> 82855GME graphics controller. With FreeBSD 6.0, I had it working nicely
>> with DRI and everything. With FreeBSD 7.2 and xorg 1.6.0, I saw some
>> peculiar problems.
>>
>> The most glaring issue was that after running X -configure for the first
>> time and testing the resulting xorg.conf file, I found that the X server
>> would not respond to the mouse or keyboard. After some digging, I found
>> that this was due to the AutoAddDevices feature (described in
>> xorg.conf(5))
>> being on by default. If AutoAddDevices is on, then AllowEmptyInput is
>> also
>> turned on, but the description for AllowEmptyInput says: "If
>> AllowEmptyInput
>> is on, devices using the kbd, mouse or vmmouse driver are ignored." I
>> don't know what's supposed to happen instead, but it wasn't working. I
>> had to add:
>>
>> Option "AutoAddDevices" "False"
>>
>> to my xorg.conf to turn this off in order for my mouse and keyboard to
>> work.
>>
>> On a related note, the X server seems to ignore a lot of what you put
>> in xorg.conf in favor of its autoselected defaults. I tried to use
>> "DefaultDepth 24" to force the screen color depth, but it seems to
>> always ignore this and use a depth of 32 bits. It seems to work ok, but
>> I thought this was odd. If I tell it to do something, it should do it.
>> This used to work in earlier X releases.
>
> Well, at least with intel driver on i915GM using anything lower than
> defaults will cause interesting artefacts on various games: alephone &
> oolite.
>
>>
>> More curiously, X -configure decided for some reason that my laptop
>> had two graphics cards instead of one. This apparently has to do with
>> the fact that the gracphic device has two PCI functions:
>>
>> vgapci0 at pci0:0:2:0: class=0x030000 card=0x031914ff chip=0x35828086
>> rev=0x02 hdr=0x00
>> vendor = 'Intel Corporation'
>> device = '82852GM/GME/GMV/PM, 855GM/GME Montara Integrated
>> Graphics
>> Device'
>> class = display
>> subclass = VGA
>> vgapci1 at pci0:0:2:1: class=0x038000 card=0x031914ff chip=0x35828086
>> rev=0x02 hdr=0x00
>> vendor = 'Intel Corporation'
>> device = '82852GM/GME/GMV/PM, 855GM/GME Montara Integrated
>> Graphics
>> Device'
>> class = display
>>
>> X -configure created a "Card" and "Screen" section for both of these,
>> even
>> though it should only have created one. I had to edit the xorg.conf to
>> remove the duplicates. (This was something else that worked correctly in
>> older versions of X.)
>>
>> Once I settled those issues, the X server worked, but I found that I
>> was unable to use DRI. FreeBSD was correctly loading the agp, drm and
>> i915 drivers, but the X server refused to activate DRI support. According
>> to the Xorg.log.0 file, it was failing to allocate a couple of regions
>> of physical memory from the AGP driver. I finally traced this down to
>> the agp_i810 code in the kernel. In agp_i810_alloc_memory(), it says:
>>
>> [...]
>> } else if (type == 2) {
>> /*
>> * Type 2 is the contiguous physical memory type, that
>> hands
>> * back a physical address. This is used for cursors on
>> i810.
>> * Hand back as many single pages with physical as the
>> user
>> * wants, but only allow one larger allocation (ARGB
>> cursor)
>> * for simplicity.
>> */
>> if (size != AGP_PAGE_SIZE) {
>> if (sc->argb_cursor != NULL)
>> return 0;
>>
>> [...]
>>
>> I'm all for simplicity, but this is bogus: the Intel video driver wants
>> to allocate three ranges of physical memory for cursors, but only the
>> first one succeeds. Two additional allocates for 40K and 16K both fail
>> because of this code.
>>
>> I ended up modifying agp_i810.c to deal with this, by allowing it to
>> allocate as many of these ranges as it wants. In the process of testing
>> this, I also ran into another problem: if you load agp.ko, drm.ko
>> and i915.ko as modules, and then try to unload them, the kernel will
>> panic in agp_i810_detach(). It seems that during unload, the drm/i915
>
> That is fixed correctly on CURRENT but not backported.
> Maybe I can track exact svn revision ... I never cared to file PR because I
> use
> only CURRENT.
Fix is from arounda 5/6 Mar from jhb at .
>
>> code will release the I/O resources allocated by the agp_i810 driver
>> before
>> the agp_i810_detach() driver gets to run. That's a shame, because
>> agp_i810_detach() needs to use them. When it tries to clear a bit in one
>> of the i810's registers, it ends up trying to use a memory mapped I/P
>> mapping that's no longer valid. As a workaround, I modified
>> agp_i810_detach() to check to see if the resources are still valid, and
>> to allocate them again if they're not. This is a hack: the DRM code
>> should be sorted out to prevent this from happening, but I'm not really
>> eager to dive into it myself.
>>
>> I put the modified Intel AGP driver code at:
>>
>> http://www.freebsd.org/~wpaul/7_2_RELEASE/agp
>>
>> To use it, copy agp_i810.c and agppriv.h to /sys/pci, then recompile
>> your kernel and/or agp.ko module.
>>
>> Once I patched the AGP driver, the X server was willing to enable DRI
>> support, but I found that GLX apps still didn't work. In particular,
>> things like the GLmatrix screen saver in KDE 4 claimed that the current
>> visual did not support the GLX extension. Looking through the log
>> file again, I saw that it said: "(==) AIGLX disabled." I considered
>> this odd, since I didn't ask to disable it. Apparently it's disabled
>> by default. I corrected this by adding:
>>
>> Option "AIGLX" "on"
>>
>> to the xorg.conf file. Finally, everything worked correctly. I was
>> even able to compile and install the latest Intel video driver (2.7.1).
>> One minor nit is that the FreeBSD AGP code doesn't support GEM, which
>> the newer X drivers seem to want. This does not appear to be a fatal
>> problem (yet).
>>
>> I put my current xorg.conf file at:
>>
>> http://www.freebsd.org/~wpaul/7_2_RELEASE/agp
>>
>> as well.
>>
>> It was a bit of a shame that I had to fight so much to get this stuff
>> to work, though now that I have I'm relatively pleased with the results.
>> I was able to get bluetooth tethering to work with my Blackberry fairly
>> easily. I still need to confirm that WPA2 works when I get to the office
>> on
>> Monday. If it does, I'm going to go through with the update.
>>
>> -Bill
>>
>> --
>> =============================================================================
>> -Bill Paul (510) 749-2329 | Senior Engineer, Master of Unix-Fu
>> wpaul at windriver.com | Wind River Systems
>> =============================================================================
>> "I put a dollar in a change machine. Nothing changed." - George Carlin
>> =============================================================================
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>
>
> --
> Paul
>
--
Paul
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