Re: [PATCH 9/9] drm/ttm: Sanity check mapping attributes on powerpc in ttm_io_prot()

On Thu, 2014-09-04 at 16:52 +0900, Michel Dänzer wrote:

...

#endif +#if defined(__powerpc__) && !defined(CONFIG_NOT_COHERENT_CACHE)

• /*
  

•  * Using a non-cachable mapping of system memory on
  

•  * cache coherent powerpc's can be fatal, let's make
  

•  * sure this doesn't happen and warn if it does. The
  

•  * only exception is powermac with AGP which has to
  

•  * take the risk.
  

•  */
  

• if (!machine_is(powermac) &&
  

•     ((caching_flags & TTM_PL_FLAG_SYSTEM) ||
  

•      (caching_flags & TTM_PL_FLAG_TT))) {
  

•         pr_err_once("TTM: Attempt to use a non-cached"
  

•                     " mapping on RAM unsupported !\n");
  

•         return tmp;
  

NAK, this breaks AGP on PowerMacs.

No it doesn't :-)

Cheers, Ben.