Hello. On 11-12-2010 22:43, Igor Plyatov wrote:
I do not test this driver, but I think it have the same problem, because it have the same algorithm for timings calculation.
I quickly looked thru both drivers and the algorithm seemed different. :-)
I don't think so...
In fact, the algorithm is slightly different.
If you will see "cycle" value greater then 63, then problem exists.
I thought the problem was with active pulse width, not total cycle time...
The problem was - the same "cycle" variable used to set up NRD_CYCLE (max value = 127) and NCS_RD_PULSE (max value = 63). Where NRD_CYCLE, NCS_RD_PULSE names from datasheet for AT91SAM9. If NCS_RD_PULSE > 63, then overflow occur and pulse is much longer then required.
Ah, NCS_RD_PULSE is different from active pulse time which is in the variable 'nrd_pulse'.
For the 132 MHz, driver use NCS_RD_PULSE = 80 at device detection moment on my board. Calculated cycle in at91_ide is the same as for pata_at91 driver.
Yes, but NCS_RD_PULSE is different in these drivers, it's cycle_time in at91_ide.c and (cycle time - 2) in the pata_at91.c... Then there should indeed be an error in at91_ide.c as well.
Generally, I does not see any reasons to use at91_ide, because ATA drivers subsystem going to replace IDE drivers.
There may be reasons -- like larger thruput in PIO mode (you have to check this though -- but generally libata seems very slow in PIO). Anyway, it doesn't mean that the bugs in IDE drivers should be ignored, and the replacemtn will not happen anytime soon (not all IDE drivers are ported to libata yet).
I will send next patch where this driver corrected and tested.
Thanks. :-)
Best regards! -- Igor Plyatov
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