From e2ebfb2142acefecc2496e71360f50d25726040b Mon Sep 17 00:00:00 2001 From: Adrian Hunter <adrian.hunter@intel.com> Date: Mon, 20 Mar 2017 19:50:29 +0200 Subject: [PATCH] mmc: sdhci: Do not disable interrupts while waiting for clock Disabling interrupts for even a millisecond can cause problems for some devices. That can happen when sdhci changes clock frequency because it waits for the clock to become stable under a spin lock. The spin lock is not necessary here. Anything that is racing with changes to the I/O state is already broken. The mmc core already provides synchronization via "claiming" the host. Although the spin lock probably should be removed from the code paths that lead to this point, such a patch would touch too much code to be suitable for stable trees. Consequently, for this patch, just drop the spin lock while waiting. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: stable@vger.kernel.org Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Tested-by: Ludovic Desroches <ludovic.desroches@microchip.com> --- drivers/mmc/host/sdhci.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 6fdd7a70f229b..9c1a099afbbec 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1362,7 +1362,9 @@ void sdhci_enable_clk(struct sdhci_host *host, u16 clk) return; } timeout--; - mdelay(1); + spin_unlock_irq(&host->lock); + usleep_range(900, 1100); + spin_lock_irq(&host->lock); } clk |= SDHCI_CLOCK_CARD_EN; -- GitLab