On Sun, 30 Aug 2020 00:00:02 -0700 Gwendal Grignou <gwendal@xxxxxxxxxxxx> wrote: > On Sat, Aug 29, 2020 at 8:54 AM Jonathan Cameron <jic23@xxxxxxxxxx> wrote: > > > > On Tue, 25 Aug 2020 17:29:45 -0700 > > Gwendal Grignou <gwendal@xxxxxxxxxxxx> wrote: > > > > > By default, the lightbar commands are set to the > > > biggest lightbar command and response. That length is greater than 128 > > > bytes and may not work on all machines. > > > But all EC are probed for lightbar by sending a get version request. > > > Set that request size precisely. > > > > > > Before the command would be: > > > cros_ec_cmd: version: 0, command: EC_CMD_LIGHTBAR_CMD, outsize: 194, insize: 128, result: 0 > > > Afer: > > > cros_ec_cmd: version: 0, command: EC_CMD_LIGHTBAR_CMD, outsize: 1, insize: 8, result: 0 > > > > > > Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx> > > Hi Gwendal, > > > > Description seems to me to suggest this is a fix? > > Are there known machines on which it doesn't work currently? > We have a prototype [without lightbar] where the command size was > limited to 128 bytes. > Given we issue a get_lightbar_version on all chromebooks, we had a > failure on this prototype. Devices with a lightbar must support a > command size greater or equal to 194 bytes. > Beside helping the prototype to boot, this patch slightly speeds up > the enumeration of devices managed by the EC. > > > > If so, please can I have a fixes tag. If it's just a precaution > > against future problems then let me know and I can add it for the > > next merge window. > Done in v3. > Note I made a mistake by sending the patch to linux-iio as it targeted > platform/chromeos. I hadn't even noticed that it wasn't in IIO. Oops :) Jonathan > > > > Thanks, > > > > Jonathan > > > > > --- > > > Changes since v1: > > > - Remove BUG and TEST fields. > > > > > > drivers/platform/chrome/cros_ec_lightbar.c | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c > > > index b59180bff5a3e..ef61298c30bdd 100644 > > > --- a/drivers/platform/chrome/cros_ec_lightbar.c > > > +++ b/drivers/platform/chrome/cros_ec_lightbar.c > > > @@ -116,6 +116,8 @@ static int get_lightbar_version(struct cros_ec_dev *ec, > > > > > > param = (struct ec_params_lightbar *)msg->data; > > > param->cmd = LIGHTBAR_CMD_VERSION; > > > + msg->outsize = sizeof(param->cmd); > > > + msg->result = sizeof(resp->version); > > > ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); > > > if (ret < 0) { > > > ret = 0; > >