On 3/17/19 3:34 PM, Greg V wrote: > > > On Sun, Mar 17, 2019 at 3:07 PM, Johannes Lundberg > <johalun0_at_gmail.com> wrote: >> Hi >> >> I'm working on making i915kms unload properly. I've come to what I think >> is the last issue. The drm driver unloads ok, the "efifb" backend is >> restored (according to logs) and vt_efifb_init() is being called but the >> screen (laptop built in display) stays black. The system seems >> operational otherwise. If I load i915kms again in this state I get back >> a visible (i915kms) framebuffer. >> >> Did we ever have this working so it's known to work? > > Recently on the linux kernel mailing list: > > http://lkml.iu.edu/hypermail/linux/kernel/1903.1/01162.html > > > Of course, once native drivers like i915 or radeon take over, such a > framebuffer is toast... [6] > > > [6] linux/drivers/gpu/drm/i915/i915_drv.c::i915_kick_out_firmware_fb() > > linux/drivers/gpu/drm/radeon/radeon_drv.c::radeon_pci_probe() > > So it seems like efifb is not supposed to work after a driver has been > loaded at least once. > > Hmm, well the code is there to handle switching back to the boot time fb. What I think is happening is that i915 powers off the displays at unload and vt doesn't know how to power on (or that it should).Received on Sun Mar 17 2019 - 15:32:49 UTC
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