lkml.org 
[lkml]   [2010]   [Sep]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [MeeGo-Dev][PATCH] Topcliff: Update PCH_I2C driver to 2.6.35
    On Fri, Sep 03, 2010 at 01:36:13PM +0100, Alan Cox wrote:
    > > +config PCH_I2C_CH_COUNT
    > > + int "PCH I2C the number of channel count"
    > > + range 1 2
    > > + depends on PCH_I2C
    > > + help
    > > + This driver is for PCH(Platform controller Hub) I2C of Topcliff which
    > > + is an IOH(Input/Output Hub) for x86 embedded processor.
    > > + The number of I2C buses/channels supported by the PCH I2C controller.
    > > + PCH I2C of Topcliff supports only one channel.
    >
    > These sort of settings need to be runtime so one kernel can be built for
    > many platform variants. In this case if I understand correctly the
    > current device only has one channel so the define could just be moved
    > into the driver for now and made a variable later as/when/if new hardware
    > with more channels appears.
    >
    >
    >
    > > +static s32 pch_wait_for_xfer_complete(struct i2c_algo_pch_data *adap)
    > > +{
    > > + s32 ret;
    > > + ret = wait_event_interruptible_timeout(pch_event,
    > > + (adap->pch_event_flag != 0), msecs_to_jiffies(50));
    > > + if (ret < 0) {
    > > + pch_err(adap, "timeout: %x\n", adap->pch_event_flag);
    > > + return ret;
    > > + }
    >
    > You are reporting a timeout when _interruptible can also be woken by a
    > signal to the process (eg the user hitting ^C)

    Sidenote: a number of embedded drivers decided to switch to
    wait_event_timeout() recently because reacting to a signal may have
    subtle issues and must be carefully implemented and tested. Stalled
    busses were often the consequence. I don't know if this applies here but
    better keep it in mind.

    --
    Pengutronix e.K. | Wolfram Sang |
    Industrial Linux Solutions | http://www.pengutronix.de/ |
    [unhandled content-type:application/pgp-signature]
    \
     
     \ /
      Last update: 2010-09-03 14:29    [W:0.023 / U:9.772 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site