Hi Bin, On 13 April 2017 at 04:00, Bin Meng <bmeng...@gmail.com> wrote: > Hi Simon, > > On Wed, Mar 22, 2017 at 4:07 AM, Simon Glass <s...@chromium.org> wrote: >> Hi, >> >> On 16 March 2017 at 08:26, Bin Meng <bmeng...@gmail.com> wrote: >>> Introduce a new CONFIG_S3_VGA_ROM_RUN option so that U-Boot can >>> bypass executing VGA roms in S3. >>> >>> Signed-off-by: Bin Meng <bmeng...@gmail.com> >>> --- >>> >>> arch/x86/Kconfig | 12 ++++++++++++ >>> drivers/pci/pci_rom.c | 14 ++++++++++++++ >>> 2 files changed, 26 insertions(+) >> >> Can this be handled at run-time, based on whether we have already run the >> ROM? >> > > I am not sure if this is what you want: > > 1). If on previous cold boot, VGA ROM has been run. Then on next S3 > boot, VGA ROM should also be run. > 2). If on previous cold boot, VGA ROM has not been run. Then on next > S3 boot, VGA ROM should not be run. > > So this is actually controlled by the CONFIG_VIDEO_VESA driver. But > this new Kconfig option aims to solve: even CONFIG_VIDEO_VESA driver > is used in a normal boot, U-Boot can still bypass the driver probe > (ROM execution) in an S3 boot to save some resume time. > >> At present, at least on ivybridge (non-FSP), the ROM execution happens >> when the device comes up. So do we actually need to run the ROM in S3 >> Or can we do it later by re-probing the driver?
With ivybridge the ROM runs when the video driver starts up. If there is no 'vidconsole' in stdout then this won't happen until someone does: setenv stdout vidconsole,serial or similar. I am not sure if this is possible with FSP machines. However in practice we are generally returning from sleep to Linux, not U-Boot. Do we have a way to know whether the ROM needs to be run (i.e. it was run before)? Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
