From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Williams Subject: Re: [PATCH] serial/8250_pci: add a quirk for the kt serial controller Date: Tue, 25 Oct 2011 13:16:34 -0700 Message-ID: <1319573794.9320.15.camel@dwillia2-mobl> References: <20111023222711.22713.11434.stgit@localhost6.localdomain6> <20111025022852.GB32457@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mga14.intel.com ([143.182.124.37]:6787 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751368Ab1JYUQv (ORCPT ); Tue, 25 Oct 2011 16:16:51 -0400 In-Reply-To: <20111025022852.GB32457@kroah.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Greg KH Cc: gregkh@suse.de, Nhan H Mai , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, alan@linux.intel.com, Dan Williams From: Dan Williams Date: Sun, 23 Oct 2011 15:06:24 -0700 Subject: [PATCH v2] serial/8250_pci: add a quirk for the kt serial controller Workaround dropped notifications in the iir register. Prevent reads coincident with new interrupt notifications by reading the iir at most once per interrupt. Reported-by: Nhan H Mai Signed-off-by: Dan Williams --- On Tue, 2011-10-25 at 04:28 +0200, Greg KH wrote: On Sun, Oct 23, 2011 at 03:27:16PM -0700, Dan Williams wrote: > > --- a/include/linux/pci_ids.h > > +++ b/include/linux/pci_ids.h [..] > Based on the comment at the top of this file, you shouldn't add this > entry to it. > > Care to redo the patch without that change? Ok, moved it to drivers/tty/serial/8250_pci.c and cleaned up the conflicting "/* This should be in linux/pci_ids.h */" comment. Thanks, Dan drivers/tty/serial/8250.c | 6 +++++- drivers/tty/serial/8250_pci.c | 17 ++++++++++++++++- include/linux/serial_core.h | 1 + 3 files changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c index 7f50999..513e728 100644 --- a/drivers/tty/serial/8250.c +++ b/drivers/tty/serial/8250.c @@ -1652,7 +1652,11 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id) up = list_entry(l, struct uart_8250_port, list); - iir = serial_in(up, UART_IIR); + if (pass_counter && up->port.flags & UPF_IIR_ONCE) + iir = UART_IIR_NO_INT; + else + iir = serial_in(up, UART_IIR); + if (!(iir & UART_IIR_NO_INT)) { serial8250_handle_port(up); diff --git a/drivers/tty/serial/8250_pci.c b/drivers/tty/serial/8250_pci.c index 3abeca2..d8fd94a 100644 --- a/drivers/tty/serial/8250_pci.c +++ b/drivers/tty/serial/8250_pci.c @@ -1092,6 +1092,14 @@ static int skip_tx_en_setup(struct serial_private *priv, return pci_default_setup(priv, board, port, idx); } +static int kt_serial_setup(struct serial_private *priv, + const struct pciserial_board *board, + struct uart_port *port, int idx) +{ + port->flags |= UPF_IIR_ONCE; + return skip_tx_en_setup(priv, board, port, idx); +} + static int pci_eg20t_init(struct pci_dev *dev) { #if defined(CONFIG_SERIAL_PCH_UART) || defined(CONFIG_SERIAL_PCH_UART_MODULE) @@ -1101,7 +1109,6 @@ static int pci_eg20t_init(struct pci_dev *dev) #endif } -/* This should be in linux/pci_ids.h */ #define PCI_VENDOR_ID_SBSMODULARIO 0x124B #define PCI_SUBVENDOR_ID_SBSMODULARIO 0x124B #define PCI_DEVICE_ID_OCTPRO 0x0001 @@ -1127,6 +1134,7 @@ static int pci_eg20t_init(struct pci_dev *dev) #define PCI_DEVICE_ID_OXSEMI_16PCI958 0x9538 #define PCIE_DEVICE_ID_NEO_2_OX_IBM 0x00F6 #define PCI_DEVICE_ID_PLX_CRONYX_OMEGA 0xc001 +#define PCI_DEVICE_ID_INTEL_PATSBURG_KT 0x1d3d /* Unknown vendors/cards - this should not be in linux/pci_ids.h */ #define PCI_SUBDEVICE_ID_UNKNOWN_0x1584 0x1584 @@ -1211,6 +1219,13 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = { .subdevice = PCI_ANY_ID, .setup = ce4100_serial_setup, }, + { + .vendor = PCI_VENDOR_ID_INTEL, + .device = PCI_DEVICE_ID_INTEL_PATSBURG_KT, + .subvendor = PCI_ANY_ID, + .subdevice = PCI_ANY_ID, + .setup = kt_serial_setup, + }, /* * ITE */ diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index a5c3114..a66484b3 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -350,6 +350,7 @@ struct uart_port { #define UPF_MAGIC_MULTIPLIER ((__force upf_t) (1 << 16)) #define UPF_CONS_FLOW ((__force upf_t) (1 << 23)) #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24)) +#define UPF_IIR_ONCE ((__force upf_t) (1 << 25)) /* The exact UART type is known and should not be probed. */ #define UPF_FIXED_TYPE ((__force upf_t) (1 << 27)) #define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28)) -- 1.7.6