This is a note to let you know that I've just added the patch titled

    Revert "serial/8250_pci: init-quirk msi support for kt serial

to my tty git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also will be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From 3579812373aba92b2f3b632bdf99329bc3c05d62 Mon Sep 17 00:00:00 2001
From: Dan Williams <[email protected]>
Date: Fri, 6 Apr 2012 11:49:37 -0700
Subject: Revert "serial/8250_pci: init-quirk msi support for kt serial
 controller"

This reverts commit e86ff4a63c9fdd875ba8492577cd1ad2252f525c.

This tried to enforce the semantics of one interrupt per iir read of the
THRE (transmit-hold empty) status, but events from other sources
(particularly modem status) defeat this guarantee.

This change also broke 8250_pci suspend/resume support as
pciserial_resume_ports() re-runs .init() quirks, but does not run
.exit() quirks in pciserial_suspend_ports() leading to reports like:

  sysfs: cannot create duplicate filename 
'/devices/pci0000:00/0000:00:16.3/msi_irqs'

...and a subsequent crash.  The mismatch of init/exit at suspend/resume
seems like a bug in its own right.

[stable: 3.3.x]
Cc: stable <[email protected]>
Acked-by: Alan Cox <[email protected]>
Cc: Sudhakar Mamillapalli <[email protected]>
Reported-by: Nhan H Mai <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/tty/serial/8250/8250_pci.c |   14 --------------
 1 file changed, 14 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_pci.c 
b/drivers/tty/serial/8250/8250_pci.c
index da2b0b0..1d4ccf8 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1118,18 +1118,6 @@ pci_xr17c154_setup(struct serial_private *priv,
        return pci_default_setup(priv, board, port, idx);
 }
 
-static int try_enable_msi(struct pci_dev *dev)
-{
-       /* use msi if available, but fallback to legacy otherwise */
-       pci_enable_msi(dev);
-       return 0;
-}
-
-static void disable_msi(struct pci_dev *dev)
-{
-       pci_disable_msi(dev);
-}
-
 #define PCI_VENDOR_ID_SBSMODULARIO     0x124B
 #define PCI_SUBVENDOR_ID_SBSMODULARIO  0x124B
 #define PCI_DEVICE_ID_OCTPRO           0x0001
@@ -1249,9 +1237,7 @@ static struct pci_serial_quirk pci_serial_quirks[] 
__refdata = {
                .device         = PCI_DEVICE_ID_INTEL_PATSBURG_KT,
                .subvendor      = PCI_ANY_ID,
                .subdevice      = PCI_ANY_ID,
-               .init           = try_enable_msi,
                .setup          = kt_serial_setup,
-               .exit           = disable_msi,
        },
        /*
         * ITE
-- 
1.7.10


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