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Date: Mon, 26 Mar 2018 18:48:06 +0200 From: Enric Balletbo Serra <eballetbo@...il.com> To: Lee Jones <lee.jones@...aro.org> Cc: Shawn Nematbakhsh <shawnn@...omium.org>, linux-kernel <linux-kernel@...r.kernel.org>, jonathanh@...dia.com, Brian Norris <briannorris@...omium.org>, Tomeu Vizoso <tomeu.vizoso@...labora.com>, Doug Anderson <dianders@...omium.org>, Alexandru M Stan <amstan@...omium.org> Subject: Re: [PATCH] mfd: cros ec: spi: Fix "in progress" error signaling Dear all, Cc'ing some more chromium folks. 2017-11-29 13:11 GMT+01:00 Lee Jones <lee.jones@...aro.org>: > On Wed, 27 Sep 2017, 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 <jonathanh@...dia.com> >> Signed-off-by: Shawn Nematbakhsh <shawnn@...omium.org> >> --- >> drivers/mfd/cros_ec_spi.c | 52 ++++++++++++++++++++++------------------------- >> 1 file changed, 24 insertions(+), 28 deletions(-) > > Applied, thanks. > This patch is a bit old and is already applied but I would like to discuss an issue that Tomeu found playing with kernelci and a Veyron Jaq attached to our lab. Seems that after this patch, the veyron jaq spits out lots of spi tranfer error messages. See full log here [1] cros-ec-spi spi0.0: spi transfer failed: -121 cros-ec-spi spi0.0: Command xfer error (err:-121) cros-ec-i2c-tunnel ff110000.spi:ec@0:i2c-tunnel: Error transferring EC i2c message -121 The issue is random, not always happens, but when happens makes cros-ec unusable. Reproduce the issue is easier if CONFIG_SMP is not set. What happens is that the master starts the transmission and the cros-ec returns an spi error event (EC_SPI_RX_BAD_DATA - data is 0xfb). The difference between after and before the patch is that now the cros-ec does not recover, whereas without this patch after some tries it succeeds (note that before the patch the affected code returned -EAGAIN whereas now returns -EREMOTEIO) I think that reverting this patch is NOT the solution, but I don't have enough knowledge yet to understand why the cros-ec fails. I need to look at the cros-ec firmware to understand better what is happening, but meanwhile, thoughts? clues? An important note is that I did not reproduce the issue on a Veyron Minnie, even with CONFIG_SMP disabled. [1] https://lava.collabora.co.uk/scheduler/job/1085493#L905 Best regards, Enric > -- > Lee Jones > Linaro STMicroelectronics Landing Team Lead > Linaro.org │ Open source software for ARM SoCs > Follow Linaro: Facebook | Twitter | Blog
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