Hello. Benjamin Herrenschmidt wrote:
Note that with all your patches applied, it doesn't seem to auto-tune the speed at boot anymore and doesn't enable DMA. I can make it do so with hdparm -d1, in which case, for example, on this wallstreet, I get MDMA2 which is correct, however, it seems to also set PIO0 which it should set PIO4...
One of the problems is that you do XFER_PIO + pio in pmac_ide_set_pio_mode(), which is no good. XFER_PIO is a bad constant name and causes that sort of confusion :-)
Yeah, it's #define'd as 0 in drivers/ide/ide-timings.h... :-/
Fix is to use XFER_PIO_0 + pio. I'll send a patch fixing that plus a few
I think Bart will just recast his patch (as usual).
other things on top of yours once I've found out what's up with DMA. I've enable autotune, I see it sending the 0x22 command, but hdparm still claims DMA isn't enabled.
Ok, there's a combination of things here:
- First, doing a set_pio from userland (hdparm -p XX) causes the kernel to disable DMA, which I think is incorrect.
That's the way ide_config_drive_speed() works.
It's not the case with 2.6.22 from my quick tests.
Which means that PIO autotuning is broken there, i.e. that ide_config_drive_speed() not called from the driver's tuneproc() method.
The problem is that ide_config_drive_speed disables DMA, but only re-enables it when setting a DMA speed.
It never "re-enables" DMA. ide_dma_host_on() method is not the same as ide_dma_on() which actually enables DMA.
I think the whole idea of having a "current speed" is bogus here, we should have a separate current DMA speed and current PIO speed. We should be able to set the PIO timings without stopping DMA, toggling DMA is a separate affair.
Agreed completely. MBR, Sergei - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
