Messages in this thread | | | Date | Mon, 12 Nov 2007 13:03:50 -0500 | From | "Ron Yorgason" <> | Subject | Better support for Delkin cardbus CF adapters -- IDE layer |
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Please CC me with any responses, I'm not on the lkml.
I'm trying to build a budget SSD using cardbus CF adapters & fast CF cards. The latest CF adapters support UDMA and PIO access methods, and CF cards support these too. The latest Delkin model boasts speeds of 45MB/s.
I currently own this card from Synchrotech, http://www.synchrotech.com/products/media-adapters-pcmcia-memory-cards_01.html as well as the latest Delkin model. The Synchrotech is recognized as a Delkin, with PCI vendor id =0x1145, device id = 0xf021. The new Delkin has device id 0xf103. I presume that in order to have the new Delkin recognized, I just need to add the appropriate line to the struct pci_device_id table.
But I'm concerned about performance. The delkin_cb.c file states:
* This is slightly peculiar, in that it is a PCI driver, * but is NOT an IDE PCI driver -- the IDE layer does not directly * support hot insertion/removal of PCI interfaces, so this driver * is unable to use the IDE PCI interfaces. Instead, it uses the * same interfaces as the ide-cs (PCMCIA) driver uses. * On the plus side, the driver is also smaller/simpler this way.
My attempts to use hdparm to turn on DMA for my device have failed. I assume this means DMA is not currently supported. In my tests, read support seems fast enough, but writing maxes out around 2MB/s. And if there is a lot of reading and writing going on (ie, trying to compile the kernel), performance is pretty abysmal. What would it take to get proper DMA support? Is it an architecture problem, in that this doesn't use the normal IDE PCI driver? Is it a lack of documentation on card specs? What can I do to help?
--Ron - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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