On Thu 03 Feb 08:44 CST 2022, Rob Herring wrote: > On Thu, Feb 3, 2022 at 5:27 AM Alex Elder <elder@xxxxxxxxxx> wrote: > > > > On 2/2/22 11:06 PM, Jakub Kicinski wrote: > > > On Tue, 1 Feb 2022 08:07:23 -0600 Alex Elder wrote: > > >> At least three platforms require the "qcom,qmp" property to be > > >> specified, so the IPA driver can request register retention across > > >> power collapse. Update DTS files accordingly. > > >> > > >> Signed-off-by: Alex Elder <elder@xxxxxxxxxx> > > >> --- > > >> > > >> Dave, Jakub, please let Bjorn take this through the Qualcomm tree. > > > > > > I don't know much about DT but the patch defining the property is > > > targeting net - will it not cause validation errors? Or Bjorn knows > > > to wait for the fixes to propagate? Or it doesn't matter? :) > > > > It might matter sometimes, but in this case it does not. > > > > If the DT property is present but never referenced by the > > code, it doesn't matter. > > > > The code in this patch looks up the DT property, and its > > behavior is affected by whether the property is there > > or not. If it's not there, it's treated as an error > > that can be safely ignored. > > > > In the case this fix is actually needed, we'll need > > both the code present and DT property defined. If > > the code is there but not the property, it's OK, but > > the bug won't be fixed quite yet. > > If there's only one possible node that qcom,qmp points to, you can > just get the node by its compatible (of_find_compatible_node()). Then > you don't need a DT update to make things work. Of course, this > doesn't work too well if there are 10 possible compatibles without a > common fallback compatible. > In one of the latest platforms there's two QMP instances, so we decided to make the reference explicit to prepare for the introduction of that. So I intend to pick this patch through the qcom tree. And we don't need to synchronize it with the net-changes; the two changes can go independently and only when they are both in place will the change take effect and the issue resolved. Regards, Bjorn
