Hi Javier, Am Samstag, 22. Juli 2023, 01:06:54 CEST schrieb Javier Martinez Canillas: > Heiko Stübner <heiko@xxxxxxxxx> writes: > > Am Dienstag, 18. April 2023, 14:11:53 CEST schrieb Javier Martinez Canillas: > >> Heiko Stübner <heiko@xxxxxxxxx> writes: > >> > Am Dienstag, 4. April 2023, 14:52:02 CEST schrieb Peter Geis: > >> >> On Tue, Apr 4, 2023 at 3:55 AM Heiko Stübner <heiko@xxxxxxxxx> wrote: > >> >> > Am Montag, 3. April 2023, 19:59:37 CEST schrieb Javier Martinez Canillas: > >> >> > > This baud rate is set for the device by mainline u-boot and is also what > >> >> > > is set in the Pinebook Pro Device Tree, which is a device similar to the > >> >> > > PinePhone Pro but with a different form factor. > >> >> > > > >> >> > > Otherwise, the baud rate of the firmware and Linux don't match by default > >> >> > > and a 'console=ttyS2,1500000n8' kernel command line parameter is required > >> >> > > to have proper output for both. > >> >> > > >> >> > The interesting question is always if this will break someone else's setup. > >> >> > I've never really understood the strange setting of 1.5MBps, but on the > >> >> > other hand it _is_ a reality on most boards. > >> > > >> >> The 1.5M baud is default because the clock structure on rockchip > >> >> devices does not allow a clean 115200 baud. By attempting to force > >> >> 115200, it will always be slightly off (either low or high depending > >> >> on how the driver decided to round). If this actually causes any > >> >> problems is the subject of much debate. > >> > > >> > thanks so much for this piece of clock-detail. As I wrote, I never really > >> > understood the why _before_ but also never cared that much to dive > >> > into it and find out. > >> > > >> > So your explanation closes one knowledge gap in my head. > >> > > >> > Thanks a lot :-) > >> > >> Did you make a decision about this? I guess the clock explanation is yet > >> another argument in favour of switching the PPP to a 1.5 Mbps baud rate ? > > > > Sorry, but no decision made here. Either way it's breaking for someone, > > which makes this quite hard. > > > > Another ping on this patch. > > > The rate accuracy is the one side, the two-boot issue is the other side. > > And mainline u-boot (and levinboot - whatever that is) provides a 3rd side. > > > > People starting with the phone probably won't replace the bootloader > > in a first step but instead might play with a system image or newer kernel. > > So if the uart will break for everyone using the default bootloader from > > the factory that is somewhat bad. > > > > Probably won't replace the DTB shipped with the firmware either? If one is > replacing the firmware provided DTB witch the one in the mainline kernel, > probably such person is also using mainline u-boot? Not necessarily. I.e. putting an extlinux.conf on an sd-card with a kernel-image and dtb is not rocket science ;-) > > I don't have a Pinephone Pro myself, so I really hoped for some Acks > > or similar to appear in the meantime. > > > > For someone like me who is only using mainline u-boot, linux, etc then > having a consistent uart baud rate across all components is really useful. > > Otherwise I either have serial console for u-boot or the kernel, but can't > have both working so is annoying. > > It would be good to have a definite answer on this. Since every time that > I try to hack on my PPP, I end changing my DTS and remember this patch :) So far people only reported "breaks my setup". I'm in a pickle here ;-) . Without anybody saying "I want to also move into this direction" I really feel I should not merge a patch that breaks other peoples setups. Heiko
