On Sat, Feb 18, 2017 at 04:31:43PM +0000, Sudip Mukherjee wrote: > On Monday 30 January 2017 11:04 PM, Sudip Mukherjee wrote: > > On Wednesday 18 January 2017 09:23 PM, Sudip Mukherjee wrote: > > > It is possible to update the backlight power and the brightness using > > > the sysfs and on writing it either returns the count or if the callback > > > function does not exist then returns the error code 'ENXIO'. > > > > > > We have a situation where the userspace client is writing to the sysfs > > > to update the power and since the callback function exists the client > > > receives the return value as count and considers the operation to be > > > successful. That is correct as the write to the sysfs was successful. > > > But there is no way to know if the actual operation was done or not. > > > > > > backlight_update_status() returns the error code if it fails. Pass that > > > to the userspace client who is trying to update the power so that the > > > client knows that the operation failed. > > > > > > Signed-off-by: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx> > > > --- > > > > A gentle ping. > > Hi Andrew, > > Its more than one month now that this patch was submitted. Can you please > take it through your tree... else it will miss the merge window. Sorry you've been waiting so long for a review. Your "gentle ping" did result in a few minor tweaks to the maintainers but what it didn't (until today) provoke was review! To be honest, the ABI changes in the patch meant I wanted to check a few things first. However prompted by this mail I've just replied with the review I *should* have sent out a week ago [asking you rather than me to fill in some details about the likely effect of the ABI change ;-) ]. BTW, I did do some archeology eariler in the week and I think the kernel has been swallowing error codes here for >10 years, so I'm curious if this is a theoretic bug fix or are you aware of some tangible problem in userspace that results from it? Daniel. -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
