[haiku-development] Re: 64 bit physical addresses
- From: Siarzhuk Zharski <zharik@xxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Tue, 22 Jun 2010 18:36:42 +0200
Hallo Ingo,
Am 22.06.2010 16:03, schrieb Ingo Weinhold:
There are a few drivers for hardware that supports 64 bit addresses (like
HDA, AHCI, some network drivers),
What is the "usual criterium" that hardware supports 64 bits addressing?
The size of corresponding registers?
I wasn't quite sure what to do what to do with several drivers for USB
devices (usb_serial, usb_audio, etc.). They allocate memory with
B_CONTIGUOUS -- usually a sign for memory for DMA -- but the physical
addresses are never retrieved as far as I have seen. I might have
overlooked something, though.
Frankly speaking this part of usb_serial was just reverse-engineered
from the Dano usb_acm so I never thought why it is done in this way.
:-\ May be it was related to some restrictions from old BeOS USB
support implementation? Regarding usb_audio - isn't it that buffers
returned to Media Server during answer on B_MULTI_GET_BUFFERS ioctl must
be physically contiguous? In case this is not required - can I jsut
allocate those buffers by call of malloc and throw away all this
area-related stuff in my implementation of usb_audio?
---
Kind Regards,
S.Zharski
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