libata PATA todo list

From: Jeff Garzik (jgarzik_at_pobox.com)
Date: 08/11/05

  • Next message: Sven Geggus: "error: structure has no member named `scsi_scan_done'" 
    Date:	Thu, 11 Aug 2005 16:54:40 -0400
To: "linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>

    Since there's been some recent interest in the subject, I thought I
    would post the PATA todo list for libata. Some of these items are from
    my memory, and some are from a list Alan was kind enough to create. The
    items verbatim from Alan are prefixed "Alan: ".

    1) Locked device/host speed

    To support devices such as those in the ide/pci/generic.c list, we need
    to ensure that libata -never- attempts to change the device speed
    (ata_dev_set_xfermode should be avoided).

    2) Simplex DMA

    PCI IDE specification has a 'simplex' DMA bit, which should be tested.
    Simplex means that only one command can be outstanding, for BOTH port0
    and port1, at any given time.

    Possibly some hosts also need Simplex DMA, but may not assert the
    standard PCI IDE Simplex DMA capability bit. I don't know.

    3) Speed change on error

    Downshift device to a slower UDMA speed, and eventually from DMA->PIO,
    as errors persist. There is no 'specified way' to do this, this is
    purely hueristic.

    4) Alan: Command filter

    Alan -- explanation?

    I know one line item here, at least: Promise controllers snoop SET
    FEATURES - XFER MODE command. We must stop command processing on ALL
    ports when this command is issued, to avoid corruption.

    5) Alan: MWDMA broken still? is piix doc correct?

    6) Alan: some PATA LBA48 devices cannot do > 256 sectors.

    7) Alan: Some ALi requires LBA48 be done via PIO. LBA28 DMA is OK.

    8) ATAPI device CDB interrupt

    Some older ATAPI devices require the OS driver to wait for an interrupt,
    after CDB is written, before command processing proceeds.

    9) ATAPI devices may delay setting DRQ=1 for up to 3ms.

    Make sure we honor the delay noted in IDENTIFY PACKET DEVICE word 0.

    10) ATAPI DMA alignment (discussed elsewhere)

    Needed even for PATA, AFAICT.

    -
    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/

  • Next message: Sven Geggus: "error: structure has no member named `scsi_scan_done'"

    Relevant Pages

    • Re: libata PATA todo list
      ... > standard PCI IDE Simplex DMA capability bit. ... > FEATURES - XFER MODE command. ... to read the multisession info to burn another ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • Re: Windows Update page hangs indefinitely
      ... I pasted in that command and received an error message saying it failed-- the ... Alan G. ... > Some have posted that registering MSXML3.DLL fixed this problem. ... > torgeir, Microsoft MVP Scripting, Porsgrunn Norway ...
      (microsoft.public.windowsupdate)
    • Re: Counting, command button and programming in VB
      ... "ElFrodo" wrote in message ... Alan skrev: ... Sub Increment() ... Right click it again and edit the text from 'Command Button1' to whatever ...
      (microsoft.public.excel.misc)
    • Re: Attention all LanMan98 users
      ... last night) show LanMan98 sending a close command with a date/ ... command and ignores the subsequent updates. ... but LanMan98 rendered them as ... Now if I could only sort out permissions - as Alan on Windows I can ...
      (comp.sys.acorn.networking)
    • Re: changing the entire network address space for the company- dos and donts!
      ... they should all self register in the 2k3 dns. ... > Hi Alan, ... You can use "Net send" command to send a network ... When the client go to work and start their computer, ...
      (microsoft.public.windows.server.active_directory)