On Wed, Sep 27, 2017 at 3:19 PM, Brian Norris <[email protected]> wrote: > On Wed, Sep 27, 2017 at 02:35:27PM -0700, Shawn Nematbakhsh wrote: >> For host commands that take a long time to process, cros ec can return >> early by signaling a EC_RES_IN_PROGRESS result. The host must then poll >> status with EC_CMD_GET_COMMS_STATUS until completion of the command. >> >> None of the above applies when data link errors are encountered. When >> errors such as EC_SPI_PAST_END are encountered during command >> transmission, it usually means the command was not received by the EC. >> Treating such errors as if they were 'EC_RES_IN_PROGRESS' results is >> almost always the wrong decision, and can result in host commands >> silently being lost. >> >> Reported-and-tested-by: Jon Hunter <[email protected]> >> Signed-off-by: Shawn Nematbakhsh <[email protected]> >> --- >> drivers/mfd/cros_ec_spi.c | 52 >> ++++++++++++++++++++++------------------------- >> 1 file changed, 24 insertions(+), 28 deletions(-) > > I'm still not sure I understand the full extent of the > originally-reported error (it's still likely a SPI transport issue?), > but I believe this patch is good anyway: > > Reviewed-by: Brian Norris <[email protected]>
Jon tracked down the root cause of the originally-reported error, but we should still land this patch, as it fixes error signaling that was previously broken. > > I wonder if we should tone down the BUG_ON()'s in drivers/mfd/cros_ec* > and drivers/platform/chrome/* too. That's basically a no-no these days, > as all of these type of things should be able to gracefully propagate > errors, no matter how "unlikely" it should be to see a crazy protocol > version number or a bad message length.
