New subject: refine xhci-plat-Fix-xhci_plat-shutdown-sequence

17 Apr 2018

在 2018-04-17 18:32，Greg KH 写道：
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On Tue, Apr 17, 2018 at 11:32:42AM +0800, leiwan@codeaurora.org wrote:
...
xhci-plat Shutdown callback should check HCD_FLAG_HW_ACCESSIBLE
before accessing any register. This should avoid hung with access
controllers which support runtime suspend
This can fix for issue of https://patchwork.kernel.org/patch/10339317/
corresponding upload in CAF:
https://source.codeaurora.org/quic/la/kernel/msm-4.4/commit/?h=LV.HB.1.1.5-0...
full patch refer attachment.

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 9b27798..bdf914d 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -702,6 +702,10 @@ static void xhci_shutdown(struct usb_hcd *hcd)
                usb_disable_xhci_ports(to_pci_dev(hcd->self.sysdev));
    spin_lock_irq(&xhci->lock);


  if (!HCD_HW_ACCESSIBLE(hcd)) {


          spin_unlock_irq(&xhci->lock);


          return;


  }
  xhci_halt(xhci);



A blank line after the if statement?
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[lei]yes
What about all of the other places in this driver that you should also
check for this?  Look at the other host controllers, shouldn't you
mirror what they are doing?
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[lei]I checked other usb host module shutdown and suspend workflow.
All usb host driver need to check hw accessable before
read/write usb register especially in runtime PM case..
And this needs a Fixes: tag, along with a cc: stable so as to properly
get backported as this is broken in some stable kernels right now.
...
...
[lei] Added by v2 patch
thanks,
greg k-h
From c03697fa259ab38d1002598ec2ccfac37607ca0b Mon Sep 17 00:00:00 2001
 From: Lei wang leiwan@codeaurora.org
Date: Tue, 17 Apr 2018 10:55:35 +0800
Subject: [PATCH v2] xhci: plat: Fix xhci_plat shutdown hung
xhci-plat Shutdown callback should check HCD_FLAG_HW_ACCESSIBLE
before accessing any register. This should avoid hung with access
controllers which support runtime suspend
Fixes: b07c12517f2a ("xhci: plat: Register shutdown for xhci_plat")
Cc: stable@vger.kernel.org
Signed-off-by: Lei wang leiwan@codeaurora.org
---
  drivers/usb/host/xhci.c | 4 ++++
  1 file changed, 4 insertions(+)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 9b27798..bdf914d 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -702,6 +702,10 @@ static void xhci_shutdown(struct usb_hcd *hcd)
         usb_disable_xhci_ports(to_pci_dev(hcd->self.sysdev));
spin_lock_irq(&xhci->lock);
+   if (!HCD_HW_ACCESSIBLE(hcd)) {
+       spin_unlock_irq(&xhci->lock);
+       return;
+   }
     xhci_halt(xhci);
     /* Workaround for spurious wakeups at shutdown with HSW */
     if (xhci->quirks & XHCI_SPURIOUS_WAKEUP)
--
1.9.1

    

Re: refine xhci-plat-Fix-xhci_plat-shutdown-sequence