[lkml]   [2011]   [Aug]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH 8/8] staging: vme: make match() driver specific to improve non-VME64x support
    On 01/08/11 11:20, Manohar Vanga wrote:
    > For jumper based boards (non VME64x), there is no mechanism
    > for detecting the card that is plugged into a specific slot. This
    > leads to issues in non-autodiscovery crates/cards when a card is
    > plugged into a slot that is "claimed" by a different driver. In
    > reality, there is no problem, but the driver rejects such a
    > configuration due to its dependence on the concept of slots.
    > This patch makes the concept of slots less critical and pushes the
    > driver match() to individual drivers (similar to what happens in the
    > ISA bus in driver/base/isa.c). This allows drivers to register the
    > number of devices that they expect without any restrictions. Devices
    > in this new model are now formatted as $driver_name-$bus_id.$device_id
    > (as compared to the earlier vme-$bus_id.$slot_number).

    I haven't got any hardware old enough to hand to play with how ISA devices get
    bound into the device model. I was thinking that we may be able to do
    vme-$bus_id.$device_id, but this would require the $device_id to be unique per
    bus, which isn't an issue on buses such as PCI (or I guess USB) where such
    enumeration is built into the spec. With the exception of VME64x, which I
    guess we should really be treating as a special case (I guess most cards in
    actual use don't follow this standard), we are much closer to the ISA bus. I
    assume that $driver_name-$bus_id.$device_id is roughly in line with how ISA
    would do this (IIRC, ther would only ever be one ISA bus on a board, so the
    bus entry wouldn't be needed, but we clearly need this)?


    Martyn Welch (Principal Software Engineer) | Registered in England and
    GE Intelligent Platforms | Wales (3828642) at 100
    T +44(0)127322748 | Barbirolli Square, Manchester,
    E | M2 3AB VAT:GB 927559189

     \ /
      Last update: 2011-08-03 11:19    [W:0.020 / U:0.608 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site