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

commit 3579812373aba92b2f3b632bdf99329bc3c05d62 upstream.

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.

Acked-by: Alan Cox <alan@linux.intel.com>
Cc: Sudhakar Mamillapalli <sudhakar@fb.com>
Reported-by: Nhan H Mai <nhan.h.mai@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index da2b0b0a183fff27805e6c5509c655c88648353d..1d4ccf8c8874573b20a15edc167f52813665da25 100644 (file)
--- 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