On Fri, 26 Apr 2019, Anup Patel wrote: > On Fri, Apr 26, 2019 at 11:51 AM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > > > On Thu, Apr 25, 2019 at 09:41:21PM -0700, Atish Patra wrote: > > > Do we even need HVC_SBI console to be enabled by default? Disabling > > > CONFIG_HVC_RISCV_SBI seems to be fine while running in QEMU. > > > > > > If we don't need it, I suggest we should remove the config option from > > > defconfig in addition to this patch. > > > > I think the whole concept of the SBI console is a little dangerous. > > It means that for one piece of physical hardware (usually the uart) > > we have two entiries (the M-mode firmware and the OS) in control, > > which tends to rarely end well. > > I think the SBI console is only useful for early SOC bringup and early > SOC debugging when most drivers are not available in upstream > kernel. It cannot (and should not) be used in production deployments. Usually the primary use-case for an abstract console interface is for desktop and server users. Usually Linux distributions want a hardware platform-specific bootloader or BIOS to specify and control the console. Originally I suspect this was implemented in the SBI for semi-hosting purposes, but that's no longer really applicable. - Paul
