On Wed, Jul 13, 2005 at 07:04:38PM +0530, [EMAIL PROTECTED] wrote: > > I ma newbie to compactflash driver , I am using mpc862 PPC processor > on my custom board having 64mb ram running linuxppc-2.4.18 kernel . > i am using Sandisk Extreme CF 1GB which is 133x high speed, but > found the performance with other kingston 1GB CF with slower speed , > is both same , CF is implemented on pcmcia port , i am not sure what > is the mode set for transfer , Feature set command is used in which > it sets the PIO mode or Multiword DMA transfer mode by specifying > its value in Sector count register , i am not able to understand in > linux kernel ide driver where this is set , is it by default set , > this mode is set or we need to set it , i think we should assign > this value , right now i am not able to trace this in my code. ,
All Compact Flash cards, in 16-bit PCMCIA card readers, operate in PIO mode 1 (polled IO, no DMA), which means you will get only about 1 MB/sec regardless of the card's claimed tranfer speed. Some cameras also only support this mode; others will run CF cars in "TrueIDE" mode, which is required to use the DMA transfer modes. There are high performance CF card readers that can use TrueIDE mode: both CardBus ones and Firewire ones. For example: http://www.dpreview.com/news/0310/03102103delkincardbustest.asp It sounds like your card reader is one of the slow 16-bit ones. -- Dave - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
