Date: Mon, 18 Mar 2019 20:02:46 +0000 From: Johannes Lundberg <johalun0@gmail.com> To: Pete Wright <pete@nomadlogic.org> Cc: Emmanuel Vadot <manu@bidouilliste.com>, FreeBSD Current <freebsd-current@freebsd.org>, Greg V <greg@unrelenting.technology> Subject: Re: Switching fb backend back to default Message-ID: <CAECmPwvaxW5Xn3y151d4NFtj=LbAx2qMrE1K2rhBbfzJAB-cXw@mail.gmail.com> In-Reply-To: <8f3432cf-b02d-67cc-f284-6fb5c2192213@nomadlogic.org> 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> <8f3432cf-b02d-67cc-f284-6fb5c2192213@nomadlogic.org>
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On Mon, Mar 18, 2019 at 19:28 Pete Wright <pete@nomadlogic.org> wrote: > > > 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 i= s > >>>>> restored (according to logs) and vt_efifb_init() is being called bu= t > >> 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 be= en > >>>> 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=E2=80=99m fine personally with losing the display wh= ile > > unloading. > > > > Keyboard input still works though and at least it doesn=E2=80=99t 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 You probably have to exit X to unload the driver so I=E2=80=99m not sure it= =E2=80=99s that much better than a reboot :) Either way, it will make simple testing a lot easier. > > -pete > > -- > Pete Wright > pete@nomadlogic.org > @nomadlogicLA > >
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