Hi Greg, On Fri, Feb 22, 2019 at 08:16:16AM +0100, Greg KH wrote: > On Fri, Feb 22, 2019 at 12:13:59AM +0200, Laurent Pinchart wrote: > > On Thu, Feb 21, 2019 at 07:57:42AM -0800, Bjorn Andersson wrote: > > > On Thu 21 Feb 04:18 PST 2019, Laurent Pinchart wrote: > > > > On Wed, Feb 20, 2019 at 10:28:29AM +0530, Vaishali Thakkar wrote: > > > > > The Qualcomm socinfo provides a number of additional attributes, > > > > > add these to the socinfo driver and expose them via debugfs > > > > > functionality. > > > > > > > > What is the use case for these attributes ? I fear they will be used in > > > > production systems, and that would require debugfs in production, which > > > > isn't a good idea. If you need to expose those attributes for anything > > > > else than debugging then we need a proper API, likely sysfs-based. > > > > > > The use case of these attributes, beyond development/debugging, are > > > unfortunately somewhat unknown and is the reason why they where moved to > > > debugfs from the earlier attempts to upstream this. > > > > > > I think the production requirements at hand prohibits debugfs to be > > > present, so attributes that are required beyond development/debugging > > > purposes would have to be migrated out to sysfs - but the idea here is > > > that such migration would have come with the missing motivation to add > > > them there today. > > > > If the use case is just debug/development, would it be enough to print > > this information in the kernel log at boot time ? I may be a bit > > paranoid, but I always worry about API abuse :-( > > Putting stuff in debugfs should be fine. No system should ever rely on > debugfs for a properly running system as it is being disabled on almost > all "sane" systems (Android included). If a vendor relies on this > information for a properly working system, then it does not belong in > debugfs. There's certainly no disagreement about that, my concern is about vendors who will enable debugfs to access information they need just because it's there. Do I assume correctly we can "break the debugfs ABI" in mainline by changing the format of the information if needed ? -- Regards, Laurent Pinchart
