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    Subject[PATCH 4.1 14/65] Disable write buffering on Toshiba ToPIC95
    Date
    4.1-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Ryan Underwood <nemesis@icequake.net>

    commit 2fb22a8042fe96b4220843f79241c116d90922c4 upstream.

    Disable write buffering on the Toshiba ToPIC95 if it is enabled by
    somebody (it is not supposed to be a power-on default according to
    the datasheet). On the ToPIC95, practically no 32-bit Cardbus card
    will work under heavy load without locking up the whole system if
    this is left enabled. I tried about a dozen. It does not affect
    16-bit cards. This is similar to the O2 bugs in early controller
    revisions it seems.

    Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=55961
    Signed-off-by: Ryan C. Underwood <nemesis@icequake.net>
    Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/pcmcia/topic.h | 16 ++++++++++++++++
    1 file changed, 16 insertions(+)

    --- a/drivers/pcmcia/topic.h
    +++ b/drivers/pcmcia/topic.h
    @@ -104,6 +104,9 @@
    #define TOPIC_EXCA_IF_CONTROL 0x3e /* 8 bit */
    #define TOPIC_EXCA_IFC_33V_ENA 0x01

    +#define TOPIC_PCI_CFG_PPBCN 0x3e /* 16-bit */
    +#define TOPIC_PCI_CFG_PPBCN_WBEN 0x0400
    +
    static void topic97_zoom_video(struct pcmcia_socket *sock, int onoff)
    {
    struct yenta_socket *socket = container_of(sock, struct yenta_socket, socket);
    @@ -138,6 +141,7 @@ static int topic97_override(struct yenta
    static int topic95_override(struct yenta_socket *socket)
    {
    u8 fctrl;
    + u16 ppbcn;

    /* enable 3.3V support for 16bit cards */
    fctrl = exca_readb(socket, TOPIC_EXCA_IF_CONTROL);
    @@ -146,6 +150,18 @@ static int topic95_override(struct yenta
    /* tell yenta to use exca registers to power 16bit cards */
    socket->flags |= YENTA_16BIT_POWER_EXCA | YENTA_16BIT_POWER_DF;

    + /* Disable write buffers to prevent lockups under load with numerous
    + Cardbus cards, observed on Tecra 500CDT and reported elsewhere on the
    + net. This is not a power-on default according to the datasheet
    + but some BIOSes seem to set it. */
    + if (pci_read_config_word(socket->dev, TOPIC_PCI_CFG_PPBCN, &ppbcn) == 0
    + && socket->dev->revision <= 7
    + && (ppbcn & TOPIC_PCI_CFG_PPBCN_WBEN)) {
    + ppbcn &= ~TOPIC_PCI_CFG_PPBCN_WBEN;
    + pci_write_config_word(socket->dev, TOPIC_PCI_CFG_PPBCN, ppbcn);
    + dev_info(&socket->dev->dev, "Disabled ToPIC95 Cardbus write buffers.\n");
    + }
    +
    return 0;
    }




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