evie/android_kernel_oneplus_msm8998
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mmc: core: Update the logic of controlling clk scaling through sysfs

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mmc clock scaling can be disabled/enabled through sysfs.
The present logic in this path deregisters/registers with devfreq
every time. Instead of this, we can simply suspend/resume the clock
scaling when requested for disabling/enabling clock scaling.
This patch updates the mentioned logic.

With original logic, observed deadlock between devfreq registration
and cmdqd thread in low memory conditions. The updated logic fixes
this deadlock condition aswell.

Change-Id: Ifee1ffbe24b13b8f5dc1c9f0579ce9ddf4b4faf3
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
This commit is contained in:
Veerabhadrarao Badiganti 2017-04-28 13:07:37 +05:30
parent 0abd412d83
commit 4c2bdc5879
1 changed files with 6 additions and 6 deletions
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12
drivers/mmc/core/host.c
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@ -653,19 +653,19 @@ static ssize_t store_enable(struct device *dev,
mmc_get_card(host->card);
if (!value) {
/*turning off clock scaling*/
mmc_exit_clk_scaling(host);
/* Suspend the clock scaling and mask host capability */
if (host->clk_scaling.enable)
mmc_suspend_clk_scaling(host);
host->caps2 &= ~MMC_CAP2_CLK_SCALE;
host->clk_scaling.state = MMC_LOAD_HIGH;
/* Set to max. frequency when disabling */
mmc_clk_update_freq(host, host->card->clk_scaling_highest,
host->clk_scaling.state);
} else if (value) {
/* starting clock scaling, will restart in case started */
/* Unmask host capability and resume scaling */
host->caps2 |= MMC_CAP2_CLK_SCALE;
if (host->clk_scaling.enable)
mmc_exit_clk_scaling(host);
mmc_init_clk_scaling(host);
if (!host->clk_scaling.enable)
mmc_resume_clk_scaling(host);
}
mmc_put_card(host->card);