Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752387AbbBXDmM (ORCPT ); Mon, 23 Feb 2015 22:42:12 -0500 Received: from cantor2.suse.de ([195.135.220.15]:60585 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752264AbbBXDmI (ORCPT ); Mon, 23 Feb 2015 22:42:08 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "Cc" From: NeilBrown To: Tony Lindgren , Felipe Balbi , Kishon Vijay Abraham I Date: Tue, 24 Feb 2015 14:40:37 +1100 Subject: [PATCH 1/4] usb: phy: twl4030: make runtime pm more reliable. Cc: linux-omap@vger.kernel.org, lkml Cc: GTA04 owners Message-ID: <20150224034036.31400.6133.stgit@notabene.brown> In-Reply-To: <20150224033730.31400.78200.stgit@notabene.brown> References: <20150224033730.31400.78200.stgit@notabene.brown> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2706 Lines: 80 A construct like: if (pm_runtime_suspended(twl->dev)) pm_runtime_get_sync(twl->dev); is against the spirit of the runtime_pm interface as it makes the internal refcounting useless. In this case it is also racy, particularly as 'put_autosuspend' is use to drop a reference. When that happens a timer is started and the device is runtime-suspended after the timeout. If the above code runs in this window, the device will not be found to be suspended so no pm_runtime reference is taken. When the timer expires the device will be suspended, which is against the intention of the code. So be more direct is taking and dropping references. If twl->linkstat is VBUS_VALID or ID_GROUND, then hold a pm_runtime reference, otherwise don't. Signed-off-by: NeilBrown --- drivers/phy/phy-twl4030-usb.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/phy/phy-twl4030-usb.c b/drivers/phy/phy-twl4030-usb.c index 8e87f54671f3..97c59074233f 100644 --- a/drivers/phy/phy-twl4030-usb.c +++ b/drivers/phy/phy-twl4030-usb.c @@ -536,8 +536,13 @@ static irqreturn_t twl4030_usb_irq(int irq, void *_twl) mutex_lock(&twl->lock); if (status >= 0 && status != twl->linkstat) { + status_changed = + (twl->linkstat == OMAP_MUSB_VBUS_VALID || + twl->linkstat == OMAP_MUSB_ID_GROUND) + != + (status == OMAP_MUSB_VBUS_VALID || + status == OMAP_MUSB_ID_GROUND); twl->linkstat = status; - status_changed = true; } mutex_unlock(&twl->lock); @@ -555,13 +560,10 @@ static irqreturn_t twl4030_usb_irq(int irq, void *_twl) */ if ((status == OMAP_MUSB_VBUS_VALID) || (status == OMAP_MUSB_ID_GROUND)) { - if (pm_runtime_suspended(twl->dev)) - pm_runtime_get_sync(twl->dev); + pm_runtime_get_sync(twl->dev); } else { - if (pm_runtime_active(twl->dev)) { - pm_runtime_mark_last_busy(twl->dev); - pm_runtime_put_autosuspend(twl->dev); - } + pm_runtime_mark_last_busy(twl->dev); + pm_runtime_put_autosuspend(twl->dev); } omap_musb_mailbox(status); } @@ -768,6 +770,10 @@ static int twl4030_usb_remove(struct platform_device *pdev) /* disable complete OTG block */ twl4030_usb_clear_bits(twl, POWER_CTRL, POWER_CTRL_OTG_ENAB); + + if (twl->linkstat == OMAP_MUSB_VBUS_VALID || + twl->linkstat == OMAP_MUSB_ID_GROUND) + pm_runtime_put_noidle(twl->dev); pm_runtime_mark_last_busy(twl->dev); pm_runtime_put(twl->dev); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/