Date: Mon, 18 Mar 2019 12:28:21 -0700 From: Pete Wright <pete@nomadlogic.org> To: Johannes Lundberg <johalun0@gmail.com>, Emmanuel Vadot <manu@bidouilliste.com> Cc: FreeBSD Current <freebsd-current@freebsd.org>, Greg V <greg@unrelenting.technology> Subject: Re: Switching fb backend back to default Message-ID: <8f3432cf-b02d-67cc-f284-6fb5c2192213@nomadlogic.org> In-Reply-To: <CAECmPwt6OqvP0oS7COtcw4DmjD3H7kEjzpMVfb34%2BoAU_WVdDw@mail.gmail.com> References: <95dfadc9-8341-b2a5-7b58-e94f46b5fa90@gmail.com> <1552836887.1930.0@unrelenting.technology> <6ea64218-2b6d-fc9a-01b5-ed07bd23c783@gmail.com> <20190317223531.b7334327a47f3579eaba98ee@bidouilliste.com> <CAECmPwt6OqvP0oS7COtcw4DmjD3H7kEjzpMVfb34%2BoAU_WVdDw@mail.gmail.com>
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On 3/17/19 2:50 PM, Johannes Lundberg wrote: > On Sun, Mar 17, 2019 at 21:35 Emmanuel Vadot <manu@bidouilliste.com> wrote: > >> On Sun, 17 Mar 2019 16:32:43 +0000 >> Johannes Lundberg <johalun0@gmail.com> wrote: >> >>> On 3/17/19 3:34 PM, Greg V wrote: >>>> >>>> On Sun, Mar 17, 2019 at 3:07 PM, Johannes Lundberg >>>> <johalun0@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). >>> >> That and if the display pipeline is de-configured or the resolution >> changed you cannot reset it to the original state. >> Unloading drm modules is only useful for testing (and finding leaks). > > Yeah a normal user would never unload it. Since I mostly ssh to my test > machines I think I’m fine personally with losing the display while > unloading. > > Keyboard input still works though and at least it doesn’t crash anymore :) > that's awesome, so in theory we will be able to upgrade the drm-kmod and use the new driver without a reboot. i like that as a hacker and end-user :) -pete -- Pete Wright pete@nomadlogic.org @nomadlogicLA
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