On Fri, Dec 13, 2019 at 09:04:54AM +0200, Felipe Balbi wrote: > > Hi, > > Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> writes: > >> Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> writes: > >>> DWC_usb32 has a feature where it can issue multiple TRB fetch requests. > >>> Add a new property to limit and only do only single TRB fetch request. > >>> > >>> Signed-off-by: Thinh Nguyen <thinhn@xxxxxxxxxxxx> > >>> --- > >>> Documentation/devicetree/bindings/usb/dwc3.txt | 2 ++ > >>> 1 file changed, 2 insertions(+) > >>> > >>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt > >>> index ff35fa6de2eb..29d6f9b1fc70 100644 > >>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt > >>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt > >>> @@ -108,6 +108,8 @@ Optional properties: > >>> - snps,num-trb-prefetch: max value to do TRBs cache for DWC_usb32. The value > >>> can be from 1 to DWC_USB32_CACHE_TRBS_PER_TRANSFER. > >>> Default value is DWC_USB32_CACHE_TRBS_PER_TRANSFER. > >>> + - snps,dis-mult-trb-fetch: set to issue only single TRB fetch request in > >>> + DWC_usb32. > >> two questions: > >> > >> - how is this different from passing 1 to the previous DT binding > > > > The previous DT binding is related to the number TRBs to cache while > > this one is related to whether the controller will send multiple > > (internal) fetch commands to fetch the TRBs. > > > >> - do we know of anybody having issues with multi-trb prefetch? > > > > No, we added this for various internal tests. > > We really a better way for you guys to have your test coverage enabled > with upstream kernel. I wonder if DT guys would accept a set of bindings > marked as "for testing purposes". In any case, we really need to enable > Silicon Validation with upstream kernel. Well, anything would be better than the endless stream of new properties. Include 'test-mode' in the property names would be fine I guess. However, why do they need to be in DT rather than module params or debugfs settings? Changing at runtime or reloading the module is a better experience than editting a DT and rebooting. Rob
