swi_vm() and busdma_swi()?

Sepherosa Ziehau sepherosa at gmail.com
Tue Nov 30 21:16:46 PST 2010

On Wed, Dec 1, 2010 at 12:19 PM, Venkatesh Srinivas
<me at endeavour.zapto.org> wrote:
> On Tue, Nov 30, 2010 at 9:42 PM, Sepherosa Ziehau <sepherosa at gmail.com> wrote:
>> On Wed, Dec 1, 2010 at 6:38 AM, Venkatesh Srinivas
>> <me at endeavour.zapto.org> wrote:
>>> Hi,
>>> In the per-mach busdma code, busdma_swi() walks a callback list under
>> busdma_swi() should be deprecated and removed, however, before that
>> you will have to fix some old drivers bus_dmamap_load()'s callback
>> logic first (all of these old drivers should be marked as non-mpsafe).
>> Best Regards,
>> sephe
> Does this mean those drivers already don't function on amd64?

If the system is short of bounce pages and the buffer to be loaded
needs to be bounced (i.e. needs to be copied to the address that is
accessible to device.  This usually happens on the system w/ more than
4Gbytes memory, since most old devices can't access physical addresses
above 4Gbytes), then those drivers will not work under these

Best Regards,

Tomorrow Will Never Die

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