Messages in this thread | | | Date | Fri, 2 Aug 2019 23:22:09 +0300 | From | Jarkko Sakkinen <> | Subject | Re: [PATCH v2 1/6] hwrng: core: Freeze khwrng thread during suspend |
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On Tue, Jul 16, 2019 at 03:45:13PM -0700, Stephen Boyd wrote: > The hwrng_fill() function can run while devices are suspending and > resuming. If the hwrng is behind a bus such as i2c or SPI and that bus > is suspended, the hwrng may hang the bus while attempting to add some > randomness. It's been observed on ChromeOS devices with suspend-to-idle > (s2idle) and an i2c based hwrng that this kthread may run and ask the > hwrng device for randomness before the i2c bus has been resumed. > > Let's make this kthread freezable so that we don't try to touch the > hwrng during suspend/resume. This ensures that we can't cause the hwrng > backing driver to get into a bad state because the device is guaranteed > to be resumed before the hwrng kthread is thawed. > > Cc: Andrey Pronin <apronin@chromium.org> > Cc: Herbert Xu <herbert@gondor.apana.org.au> > Cc: Duncan Laurie <dlaurie@chromium.org> > Signed-off-by: Stephen Boyd <swboyd@chromium.org>
This does not need a fixes tag?
/Jarkko
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