Re: RFC: PCI SD host controller driver & mmc/mmcsd modules improvements

From: Zaphod Beeblebrox <zbeeble_at_gmail.com>
Date: Mon, 6 Oct 2008 01:26:19 -0400
On Sat, Sep 27, 2008 at 5:43 PM, Alexander Motin <mav_at_freebsd.org> wrote:

> Hi.
>
> I would like to present initial revision of my generic PCI SD Host
> Controller driver (sdhci). It support PCI devices with class 8 and subclass
> 5 according to SD Host Controller Specification. With some limitations it
> successfully works on my Acer TM6292 notebook with ENE CB714 card reader.
>


> Things that are not working yet:
>  - DMA modes (code is written, but as my controller looks like has broken
> DMA I have no ability to debug it),
>  - card insert/remove detection (need more thinking), you should reload mmc
> module to rescan cards,
>  - SDHC and MMC cards (have no such cards now to debug that code), only
> standard capacity SD Memory cards up to 4GB size are supported now,
>  - high speed (double rate) bus mode (need more thinking and DMA support).


Most 4G cards are SDHC that I've seen.  The notes on this that I've read
talk about the fact that you can have a 4G regular SD card but that many
(most) devices don't support it because of the need for a larger FAT to
support 4G.

I have two laptops with these controllers, but I have only SDHC media (4 and
8 gig cards).
Received on Mon Oct 06 2008 - 03:52:41 UTC

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