Kévin Redon has posted comments on this change. ( https://gerrit.osmocom.org/10313 )
Change subject: add synchronous UART transmission and use it in exceptions ...................................................................... Patch Set 2: > (1 comment) > > I think in general I would have preferred to simply use a separate > Uart transmit function from the hardirq handlers. Either by > explicitly changing those calls away from printf, or by > catching/redirecting printf using a #define that's #included only > in the exceptions.c file in order to bypass normal printf(). I've added an additional prinft for synchronous transfer. A define in the default exceptions redirects to this new printf. > Another idea that just comes to my mind: Couldn't we simply check > some CPU status flags to know that we're in an exception or in an > interrupt? This way the decision to bypass the ring buffer could > be entirely automatic without any explcit calls to disable the > buffer, or any of the hacks I described above? I would suggest to > look into this. If it turns out it's not that simple, please > report back and we can merge your current patch as-is. I also thought of this, but we don't want a synchronous transfer in every ISR (e.g. when TRACE_LOG is used in ISR for ERROR level). We only want synchronous transfer in final handler (with blocking while). I also think blocking until the transfer is complete is important. This would "remove" the UART 1-byte buffer, but at this point it just adds a 1-byte transfer delay for the whole printf. The benefit is that we are sure the complete string is printed (e.g. it a handler would reset after a print, the last by would not have time to be transferred) -- To view, visit https://gerrit.osmocom.org/10313 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: simtrace2 Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I1b4ace5185cf2dc32684934ed12bf6a8682e9bad Gerrit-Change-Number: 10313 Gerrit-PatchSet: 2 Gerrit-Owner: Kévin Redon <[email protected]> Gerrit-Reviewer: Harald Welte <[email protected]> Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: Kévin Redon <[email protected]> Gerrit-Comment-Date: Sat, 04 Aug 2018 09:32:05 +0000 Gerrit-HasComments: No Gerrit-HasLabels: No
