Re: libata pata_pdc2027x success on sparc64
From: Mikael Pettersson
Date: Wed Aug 09 2006 - 12:13:51 EST
Sergei Shtylyov writes:
> Mikael Pettersson wrote:
> > > The libata version has three improvements compared to the IDE version.
> > >
> > > 1. The PLL calibration patches in the above URLs (for IDE)
> > > still need more improvement as done in the pdc_read_counter()
> > > of the libata version.
> > >
> > > 2. The Promise 2027x adapters check the "set features - xfer mode"
> > > and set the timing register automatically. However, the automatically
> > > set values are not correct under 133MHz. Libata has a hook
> > > pdc2027x_post_set_mode() to set the values back by software.
> > >
> > > 3. ATAPI DMA is supported (please see pdc2027x_check_atapi_dma()).
> > > Maybe we also need to add this to the IDE version.
> > Do you know how large the difference is between the 20267 (old driver)
> > and the 20269 (new driver) in the areas touched by these patches?
> Immense. They belong to the different families, register compatibe only in
> the standard PCI/BM IDE regisrer set -- hence was the driver split.
> > Long ago I tried a 20267 PCI card in my PowerMac, and it had the same
> > issues that the 20269 card had. So I'm interested in porting the
> > calibration/timing fixes to pdc202xx_old.c.
> They don't apply to this driver at all. The "older" chip family didn't
> have the PLL to calibrate. It must be some different issue.
OK, in that case let's forget about the 20267. It's not _that_ important :-)
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