Re: [Mesa3d-dev] Re: [Xpert]mesa assuming glibc 2.2? (Cannot compile 4.1 on RedHat 6.2)

[David D. <da...@XF...>]

On Tue, Jun 05, 2001 at 09:56:44AM -0600, Brian Paul wrote:
>"Marcelo E. Magallon" wrote:
>> 
>> >> Brian Paul <br...@va...> writes:
>> 
>>  > If anyone knows a solution to this I'd like to hear it.
>> 
>>  Sometime ago I submitted a patch for this (#403332).  The comment
>>  reads:
>> 
>>  | If the use of KATMAI instructions is enabled, on linux it's necessary
>>  | to have recent kernel headers installed (these are coupled to the C
>>  | library, so suggesting to place/change a link in /usr/src/ is not
>>  | advisable). There are two options for it's detection at compile time,
>>  | one is using LINUX_KERNEL_VERSION, what this patch does, the other is
>>  | checking for X86_FXSR_MAGIC to be defined. I'm sure Gareth can make a
>>  | recommendation as to which is better. With either of them, I think
>>  | it's important to provide the user with an error that at least
>>  | suggests a course of action (the current one goes along the lines of
>>  | "magic is not a member of structure sigcontext", IIRC)
>> 
>>  | The patch uses 2.4.0 as a reference point, I'm not really sure when
>>  | the SSE support was introduced in the kernel, but it's not on the
>>  | 2.2.18 I looked at.
>> 
>>  The patch, which is not on SF (weird) is basically:
>> 
>> Index: extras/Mesa/src/X86/common_x86.c
>> ===================================================================
>> RCS file: /cvsroot/dri/xc/xc/extras/Mesa/src/X86/common_x86.c,v
>> retrieving revision 1.10
>> diff -u -r1.10 common_x86.c
>> --- extras/Mesa/src/X86/common_x86.c    2001/02/12 20:42:42     1.10
>> +++ extras/Mesa/src/X86/common_x86.c    2001/06/05 15:22:50
>> @@ -88,6 +88,11 @@
>>  extern void gl_test_os_katmai_exception_support( void );
>> 
>>  #if defined(__linux__) && defined(_POSIX_SOURCE)
>> +#include <linux/version.h>
>> +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,0)
>> +#error "linux headers older than 2.4.0 don't provide support for SSE."
>> +#endif
>> +
>>  static void sigill_handler( int signal, struct sigcontext sc )
>>  {
>>     message( "SIGILL, " );
>> 
>>  Granted, it's not the best solution, but it's at least an useful error.
>>  Some conditionals on the configuration files would do it, too.
>>  (HAVE_LINUX_2_4_HEADERS, Imakefile style).  The point is, you need 2.4
>>  kernel headers to compile this.
>
>
>I'd like to see a solution that doesn't interupt compilation.  That
>is, if we can't use SSE at compile time, it should just be disabled,
>perhaps with a warning.
>
>The trick is there was a patch to Linux 2.2.x that added SSE so just
>testing for kernel >= 2.4.0 isn't enough.  Does the presense of
>X86_FXSR_MAGIC ensure that the _fpstate.magic field exists?

For builds within XFree86, linux.cf already has the kernel version check:

#ifndef HasKatmaiSupport
#  ifdef i386Architecture
#    if OSMajorVersion > 2 || (OSMajorVersion == 2 && OSMinorVersion >= 4)
#      define HasKatmaiSupport          YES
#    else
#      define HasKatmaiSupport          NO
#    endif
#  else
#    define HasKatmaiSupport            NO
#  endif
#endif

It assumes that the kernel headers will be found for the build though.

David
--
David Dawes                                      Email: da...@XF...
Founder/President, The XFree86 Project, Inc      Phone: +1 510 687 6857
http://www.xfree86.org/