Re: Badness in map_area_pte

[Bob Breuer <breuerr@mc.net>]

William Lee Irwin III wrote:
> Bob Breuer wrote:
> 
>>>At this point, I am guessing that some pte's allocated for the 
>>>framebuffer are being wrongly re-used when loading the module.
> 
> 
> On Sat, Jan 15, 2005 at 08:25:35PM -0600, Bob Breuer wrote:
> 
>>The cg14 driver is not remapping the framebuffer, and is using the mappings 
>>that were setup by the prom and recreated in linux from 
>>srmmu_inherit_prom_mappings().
>>How can we tell vmalloc not to step on that area of memory?  Is it just 
>>from VMALLOC_START to END?  Let's see, for 2.6 those are 0xfe600000 and 
>>0xffc00000.  The prom mapped the cg14 to 0xfe700000 (8MB ram) and 
>>0xffec0000 (registers).  Hmm, a bit of overlap there...  And 2.4 had 
>>VMALLOC_START at 0xfe300000.  So it would seem that if the total vmalloc'ed 
>>memory goes above 1 meg for me, 2.6 will have problems, but 2.4 will still 
>>be fine.
> 
> 
> This sounds like a real problem. What happens if you move VMALLOC_START
> to where it was in 2.4.x?
> 

Yes, changing it back fixes my problem for now.

The bitkeeper comments say it was changed 4 months ago to fix a framebuffer 
on a SparcStation 2.  Looks like we need something more dynamic to cover all 
the bases.

Bob