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/core/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/mmc/core/core.c') diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 3bf1c462eded..c1893c9c3c31 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2416,7 +2416,8 @@ void mmc_start_host(struct mmc_host *host) { host->f_init = max(freqs[0], host->f_min); host->rescan_disable = 0; - mmc_power_up(host); + if (!(host->caps2 & MMC_CAP2_NO_PRESCAN_POWERUP)) + mmc_power_up(host); mmc_detect_change(host, 0); } -- cgit v1.2.3