From 0d3e3350d5871c53464be4c92d57198744247005 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Thu, 4 Apr 2013 16:41:06 +0300 Subject: mmc: core: fix performance regression initializing MMC host controllers Commit fa5501890d8974301042e0202d342a6cbe8609f4 introduced a performance regression by adding mmc_power_up() to mmc_start_host(). mmc_power_up() is not necessary to host controller initialization, it is part of card initialization and is performed anyway asynchronously. This patch allows a driver to leave the power up in asynchronous code (as it was before). On my current target platform this reduces driver initialization from: [ 1.313220] initcall sdhci_acpi_driver_init+0x0/0x12 returned 0 after 102008 usecs to this: [ 1.217209] initcall sdhci_acpi_driver_init+0x0/0x12 returned 0 after 8331 usecs Signed-off-by: Adrian Hunter Acked-by: Ulf Hansson Signed-off-by: Chris Ball --- drivers/mmc/host/sdhci-acpi.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/mmc/host/sdhci-acpi.c') diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c index 2592dddbd965..7bcf74b1a5cd 100644 --- a/drivers/mmc/host/sdhci-acpi.c +++ b/drivers/mmc/host/sdhci-acpi.c @@ -195,6 +195,8 @@ static int sdhci_acpi_probe(struct platform_device *pdev) host->mmc->pm_caps |= c->slot->pm_caps; } + host->mmc->caps2 |= MMC_CAP2_NO_PRESCAN_POWERUP; + err = sdhci_add_host(host); if (err) goto err_free; -- cgit v1.2.3