On Fri, 26 Apr 2019, Anup Patel wrote:
On Fri, Apr 26, 2019 at 11:51 AM Christoph Hellwig hch@infradead.org 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