Re: SATA status reports update

From: Robert Hancock
Date: Sat Sep 30 2006 - 12:38:16 EST

Prakash Punnoor wrote:
Am Freitag 29 September 2006 12:03 schrieb Jeff Garzik:
Prakash Punnoor wrote:
Well, how would one debug it w/o hw docs? Or is it possible to compare
the patch with a working driver for another chipset?
Well, it is based off of the standard ADMA[1] specification, albeit with
modifications. There is pdc_adma.c, which is also based off ADMA. And
the author (from NVIDIA) claims that the driver worked at one time, so
maybe it is simply bit rot that broke the driver.

Well, I tried to hack the patch into 2.6.18 driver, but wasn't very successful. It migt be also due to the case that I have a MCP51 chipset and if I read the patch correctly it isn't designed to activate ADMA on MCP51. Do you know whether MCP51 knows ADMA? If not, how is NCQ to be activated on MCP51? According to and windows user reports MCP51 does know NCQ.

The same Windows driver supports all of:

CK804SSS="NVIDIA nForce4 Serial ATA Controller"
MCP51S="NVIDIA nForce 430/410 Serial ATA Controller"
MCP55S="NVIDIA nForce 590/570/550 Serial ATA Controller"

From looking at the patch it seems to only use the ADMA code for CK804 only. Probably the others use the same programming interface (though who knows if they implemented a totally different one in the same Windows driver). I guess you could try hacking it to use ADMA on that controller and see what happens..

I have an nForce4 board and it would be nice if we could have working NCQ, though I haven't really played with libata before. I may experiment with it a bit, though - Jeff, what kernel was this patch against? It obviously won't apply to current -mm, that nv_host_desc structure it is patching is gone for one thing..

Robert Hancock Saskatoon, SK, Canada
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