On Mon, 3 Dec 2018 at 14:45, Laszlo Ersek <[email protected]> wrote: > > On 12/03/18 11:03, Udit Kumar wrote: > > Hi Laszlo > > > >> Are you using the latest edk2? > > Yes, when I hit the bug, first step was to move to latest edk2. But this > > didn't helped. > > > > I am not sure, why we are keeping PL011 Fifo mode off in default > > configuration. > > Sorry, I don't know: although the subject logic has gone through several > updates over time, the default that you point out seems to go back to > commit 051e63bb551a ("ArmPlatformPkg/PL011Uart: Allowed to change UART > settings in its initialization function", 2012-02-29). And that commit > doesn't explain the default. >
The default setting for gEfiMdePkgTokenSpaceGuid.PcdUartDefaultReceiveFifoDepth is 1 not 0, and so you will end up with a 1 character FIFO setting. I wonder if we could improve PL011UartInitializePort () in PL011UartLib to deal with this better. Note that this also affects platforms that can switch between DT and ACPI boot: the same PL011 is described as a 'dumb' SBSA uart in the latter case, and so it is up to the firmware to configure the UART FIFO correctly, or you will not be able to use the UART under the ACPI OS. _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
