From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: [PATCH 01/25] mmc: sdhci: Do not disable interrupts while waiting for clock Date: Mon, 20 Mar 2017 19:50:29 +0200 Message-ID: <1490032253-6030-2-git-send-email-adrian.hunter@intel.com> References: <1490032253-6030-1-git-send-email-adrian.hunter@intel.com> Return-path: Received: from mga01.intel.com ([192.55.52.88]:15128 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756528AbdCTR7j (ORCPT ); Mon, 20 Mar 2017 13:59:39 -0400 In-Reply-To: <1490032253-6030-1-git-send-email-adrian.hunter@intel.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ulf Hansson Cc: linux-mmc , Al Cooper , Jaedon Shin , Haibo Chen , Dong Aisheng , Shawn Lin , Douglas Anderson , Zach Brown , Ludovic Desroches , Jisheng Zhang , Yangbo Lu , Jaehoon Chung , Weijun Yang , Barry Song , Peter Griffin , Lee Jones , Jon Hunter , Harjani Ritesh 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 Cc: stable@vger.kernel.org --- 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 6fdd7a70f229..9c1a099afbbe 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; -- 1.9.1