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SubjectRe: [PATCH] [OLPC] sdhci: add quirk for the Marvell CaFe's interrupt timeout
On Mon, 23 Jun 2008 10:13:52 -0400
Andres Salomon <dilinger@queued.net> wrote:

>
> The CaFe chip has a hardware bug that ends up with us getting a timeout
> value that's too small, causing the following sorts of problems:
>
> [ 60.525138] mmcblk0: error -110 transferring data
> [ 60.531477] end_request: I/O error, dev mmcblk0, sector 1484353
> [ 60.533371] Buffer I/O error on device mmcblk0p2, logical block 181632
> [ 60.533371] lost page write due to I/O error on mmcblk0p2
>
> Presumably this is an off-by-one error in the hardware. Incrementing
> the timeout count value that we stuff into the TIMEOUT_CONTROL register
> gets us a value that works. This bug was originally discovered by
> Pierre Ossman, I believe.
>
> [thanks to Robert Millan for proving that this was still a problem]
>
> Signed-off-by: Andres Salomon <dilinger@debian.org>
> ---
> drivers/mmc/host/sdhci.c | 12 +++++++++++-
> 1 files changed, 11 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 5b74c8c..2b3f06a 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -57,6 +57,8 @@ static unsigned int debug_quirks = 0;
> #define SDHCI_QUIRK_RESET_AFTER_REQUEST (1<<8)
> /* Controller needs voltage and power writes to happen separately */
> #define SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER (1<<9)
> +/* Controller has an off-by-one issue with timeout value */
> +#define SDHCI_QUIRK_INCR_TIMEOUT_CONTROL (1<<10)
>
> static const struct pci_device_id pci_ids[] __devinitdata = {
> {
> @@ -134,7 +136,8 @@ static const struct pci_device_id pci_ids[] __devinitdata = {
> .device = PCI_DEVICE_ID_MARVELL_CAFE_SD,
> .subvendor = PCI_ANY_ID,
> .subdevice = PCI_ANY_ID,
> - .driver_data = SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER,
> + .driver_data = SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER |
> + SDHCI_QUIRK_INCR_TIMEOUT_CONTROL,
> },
>
> {
> @@ -479,6 +482,13 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
> break;
> }
>
> + /*
> + * Compensate for an off-by-one error in the CaFe hardware; otherwise,
> + * a too-small count gives us interrupt timeouts.
> + */
> + if ((host->chip->quirks & SDHCI_QUIRK_INCR_TIMEOUT_CONTROL))
> + count++;
> +
> if (count >= 0xF) {
> printk(KERN_WARNING "%s: Too large timeout requested!\n",
> mmc_hostname(host->mmc));

This is needed in 2.6.26, I assume?

If so, I can merge it unless Pierre has objections?

And it will cause conflicts with overlapping changes in linux-next.



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