On 03/09/07, Eddie Hung <eddie.hung@xxxxxxxxx> wrote: > On 03/09/07, Tejun Heo <htejun@xxxxxxxxx> wrote: > > The report mechanism is simple and the controller doesn't have much to > > do with it. Bridge chip may affect it but I'm doubtful. > > > > > > > My X41 has a 1.5Ghz P4M, and a 0.1MB/s hit (if it is using PIO) is > > > hardly going to make a dent - I'm fairly sure that it is spending most > > > of its time waiting for IO, but I shall take a deeper look tonight. > > > > The beautiful thing about PIO is that it doesn't matter how fast your > > cpu is. Faster CPUs will just burn more cycles while transferring data > > at the same measly speed. :-) > > Ahh yes, that makes sense - it's more about the time it takes rather > than the cycles consumed... > > > > What's confusing me is that my 40MB/s card only supporting MWDMA2 - > > > which offers only a max transfer rate of 16.7MB/s - how have other > > > people achieved 30MB/s then!?! (I'm referring to an ICH8 user who > > > claims he has here, with a very similar CF card: > > > http://www.opensubscriber.com/message/linux-ide@xxxxxxxxxxxxxxx/6818048.html > > > > Whatever the device is, it should support UDMA to do 30MB/s. MWDMA2 > > just can't reach that speed electronically. > > Sorry, I was implying that he mustn't be using MWDMA to achieve them > sort of speeds, and indeed from his hdparm -I he is not. I'm currently > in touch with an X41 user who has reported success with a different CF > card, who is getting 35MB/s and 0.2ms access time under Windows > *drool* > > > > Also, does libATA support the PIO5 and PIO6 modes, which according to > > > Wikipedia are not part of the ATA standard, but the CF 2.0 standard? > > > (source: http://en.wikipedia.org/wiki/Programmed_input/output ) > > > > I dunno much about those fancy PIO modes. Maybe Alan knows? > > From the wiki article, I get the impression that the faster PIO modes > are simply lower cycle times, with everything else more or less the > same - so that shouldn't be too hard to add if it's not already there? > More importantly I guess, I wonder if hdparm -I supports the detection > of pio5 or pio6? I'll dig into the sources later. > > Thanks, > > Eddie > I am pursuing another possibility: the CF card is not a genuine Sandisk one at all, especially as it was off eBay! I compared my hdparm -I with the one in the thread above (which as I've found out is a Sandisk Extreme II 4GB) and there are big differences, namely the model number, serial number and firmware version. This might explain everything! Eddie - 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
