* Nishanth Menon <nm@xxxxxx> [151022 19:49]: > On 10/22/2015 08:01 PM, Praneeth wrote: > > Hi Nishanth, > > > > On 10/22/2015 07:24 PM, Praneeth Bajjuri wrote: > >> From: "J.D. Schroeder" <jay.schroeder@xxxxxxxxxx> > >> > >> UART4 low level debug support. This helps in debugging with UART4 > >> serial console output on DRA7 based platforms. > >> > >> Extending the following fix for UART4. > >> commit 1c7e36bfc3e2 ("ARM: DRA7: hwmod: Fix boot crash with DEBUG_LL > >> enabled on UART3") > >> > >> For using DEBUG_LL, enable CONFIG_DEBUG_OMAP4UART4 in menuconfig. > >> On DRA7, UART4 hwmod doesn't have this flag enabled, > >> failure observed when UART4 is used for low level debugging. > >> > >> Hence, Enable DEBUG_OMAP4UART4_FLAGS for UART4 hwmod. > > Replying to your question from V1 > > > > we have DRA7 based platforms with UART1/UART3/UART4 for serial console. > > > > 1,3 seems to be already fixed in mainline. Hence sending fix only for 4 > > Tony or others can comment. IMHO, 1c7e36bfc3e2 is an excellent example. > it considered just UART3 as the missing thing. UART1 was already done. > now, we have UART4, tomorrow, some other board will have UART2, how many > patch on top of patch do we want to do for the same problem? > > Phytech > http://phytec.com/site/assets/files/2109/phytec_am57x-som_pb_release.pdf > is a SOM module (page 2 - UART5,3 go to expansion connector). > > And then you have > http://www.compulab.co.il/products/computer-on-modules/cl-som-am57x-ti-am5728-am5718-system-on-module/#diagram > > When we see issues like these that are probably symptoms, we might as > well try and do as wide a solution as necessary. > > if we stick with the rule that we will only enable DEBUG_LL only for > those boards that are actually in upstream, then obviously, this patch > should be dropped. > > I do think, personally, that by introducing changes such as enabling > DEBUG_LL for all ports, we are making the "evil vendor tree" less > different from upstream and hence reduce cost of upstreaming - hopefully > this might help motivate various product folks to actually provide > upstream support for their products (N900 is still my favourite phone > which actually works in upstream kernel- thanks to a lot of passionate > community folks) - we really want to see more of those actual products > function and be maintained with upstream kernel. Yeah it's not a nice setup right now.. But I'll apply this anyways as we're still very much depending on the DEBUG_LL for board bring up. We should just move to moving CONFIG_SERIAL_EARLYCON with earlycon on the cmdline or stdout-path = "serial3:115200n8" in the dts chosen. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html