Messages in this thread | | | Date | Fri, 10 Dec 1999 11:16:57 +0100 | From | Pavel Machek <> | Subject | Re: linux-2.3.31: drivers/char/drm/drmP.h does not allow 386 build |
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Hi!
> > As of linux-2.3.31, drivers/char/drm/drmP.h deliberately aborts > > the compile the CPU type in the kernel build is configured to be 386. > > The problem is that this is the way that one builds a kernel that can > > run on any x86 (to avoid things like generating the BSWAP instruction, > > which the 386 lacks). It does not necessarily mean that the CPU is > > actually a 386. This change to drmP.h makes it impossible to build a fully > > configured for the full x86 processor family. If there is some reason > > why the "direct rendering infrastructure" should not run on a 386, then > > this check should be done at run time, not compile time. > > We need to use the CMPXCHG instruction for fast locking, and this > instruction is not available on the 386. Would it be sufficient if we > compiled using the CMPXCHG instruction and then did a run-time test for the > 386 and never executed this instruction? This is approximately what we did > before 2.3.31. (386s are too slow to make direct-rendering a viable > option, so we don't support the DRI on 386s [and all modern graphics cards > are PCI or AGP, and most (all?) 386s don't have these busses > available].)
Actually there were rare 386's with PCI slots. :-).
Pavel -- I'm really pavel@ucw.cz. Look at http://195.113.31.123/~pavel. Pavel Hi! I'm a .signature virus! Copy me into your ~/.signature, please!
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