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    SubjectRe: [PATCH v2] gpio: fix deferred probe detection for legacy API
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    Hi Alexander,

    On Tue, Dec 2, 2014 at 3:15 PM, Alexandre Courbot <acourbot@nvidia.com> wrote:
    > Commit 14e85c0e69d5 ("gpio: remove gpio_descs global array") changed
    > gpio_to_desc()'s behavior to return NULL not only for GPIOs numbers
    > not in the valid range, but also for all GPIOs whose controller has not
    > been probed yet. Although this behavior is more correct (nothing hints
    > that these GPIO numbers will be populated later), this affects
    > gpio_request() and gpio_request_one() which call gpiod_request() with a
    > NULL descriptor, causing it to return -EINVAL instead of the expected
    > -EPROBE_DEFER for a non-probed GPIO.
    >
    > gpiod_request() is only called with a descriptor obtained from
    > gpio_to_desc() from these two functions, so address the issue there.
    >
    > Other ways to obtain GPIOs rely on well-defined mappings and can thus
    > return -EPROBE_DEFER only for relevant GPIOs, and are thus not affected
    > by this issue.
    >
    > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
    > Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
    > ---
    > v2:
    > - Add Geert's Tested-by
    > - Only display scary warning on gpio_to_desc() is the GPIO is outside
    > the valid range (pre gpio_desc array removal behavior)

    Thanks, the scary warnings are gone, together with a few superfluous
    "gpio-0 (?): gpiod_request: status -517" messages.

    Have a good night!

    Gr{oetje,eeting}s,

    Geert

    --
    Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

    In personal conversations with technical people, I call myself a hacker. But
    when I'm talking to journalists I just say "programmer" or something like that.
    -- Linus Torvalds


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