On Wed, Dec 11, 2013 at 11:20:59AM +0800, Dong Aisheng wrote: > No, the max_to is the max timeout counter value, you need to divide it > by the timeout clock > to get the timeout time. > The defined of this API is return the max timeout value in > miliseconds, so you need to > divide the clock by 1000. > None of these handles the detail bout discard_to. Let me start it over again. Here is basically what your patch does. - mmc->max_discard_to = (1 << 27) / host->timeout_clk; + if (host->ops->get_max_timeout) + mmc->max_discard_to = host->ops->get_max_timeout(host); The only thing that does not work for you in the existing code is the (1 << 27) part, right? If so, why not just create a platform hook to return the correct thing for you platform, i.e. (1 << 28)? if (host->ops->get_max_timeout) mmc->max_discard_to = host->ops->hook_foo(host); unsigned int esdhc_hook_foo(struct sdhci_host *host) { struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); struct pltfm_imx_data *imx_data = pltfm_host->priv; return esdhc_is_usdhc(imx_data) ? 1 << 28 : 1 << 27; } Such patch will be ease to be understood and less offensive to the existing code, no? Shawn -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html