From: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
To: Alex Deucher <alexdeucher@gmail.com>
Cc: "open list:EFIFB FRAMEBUFFER DRIVER"
<linux-fbdev@vger.kernel.org>,
kexec@lists.infradead.org,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
kernel@gpiccoli.net, "Baoquan He" <bhe@redhat.com>,
"Samuel Iglesias Gonsálvez" <siglesias@igalia.com>,
"xinhui pan" <Xinhui.Pan@amd.com>,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
pjones@redhat.com, "Gerd Hoffmann" <kraxel@redhat.com>,
"Deucher, Alexander" <alexander.deucher@amd.com>,
"Dave Young" <dyoung@redhat.com>,
"Christian Koenig" <christian.koenig@amd.com>,
"Vivek Goyal" <vgoyal@redhat.com>
Subject: Re: Reuse framebuffer after a kexec (amdgpu / efifb)
Date: Thu, 9 Dec 2021 15:17:51 -0300 [thread overview]
Message-ID: <eaea0143-a961-b83c-3c6c-4d612cd003bc@igalia.com> (raw)
In-Reply-To: <CADnq5_N9ptK4c86LO77YcrF5_M==hket+L7eYjsGCaKbORO=ug@mail.gmail.com>
Thanks again Alex! Some comments inlined below:
On 09/12/2021 15:06, Alex Deucher wrote:
> Not really in a generic way. It's asic and platform specific. In
> addition most modern displays require link training to bring up the
> display, so you can't just save and restore registers.
Oh sure, I understand that. My question is more like: is there a way,
inside amdgpu driver, to save this state before taking
over/overwriting/reprogramming the device? So we could (again, from
inside the amdgpu driver) dump this pre-saved state in the shutdown
handler, for example, having the device in a "pre-OS" state when the new
kexec'ed kernel starts.
>
> The drivers are asic and platform specific. E.g., the driver for
> vangogh is different from renoir is different from skylake, etc. The
> display programming interfaces are asic specific.
Cool, that makes sense! But if you (or anybody here) know some of these
GOP drivers, e.g. for the qemu/qxl device, I'm just curious to
see/understand how complex is the FW driver to just put the
device/screen in a usable state.
Cheers,
Guilherme
WARNING: multiple messages have this Message-ID (diff)
From: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
To: Alex Deucher <alexdeucher@gmail.com>
Cc: "open list:EFIFB FRAMEBUFFER DRIVER"
<linux-fbdev@vger.kernel.org>, "xinhui pan" <Xinhui.Pan@amd.com>,
"Baoquan He" <bhe@redhat.com>,
"Samuel Iglesias Gonsálvez" <siglesias@igalia.com>,
kernel@gpiccoli.net, kexec@lists.infradead.org,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
pjones@redhat.com,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
"Deucher, Alexander" <alexander.deucher@amd.com>,
"Dave Young" <dyoung@redhat.com>,
"Christian Koenig" <christian.koenig@amd.com>,
"Vivek Goyal" <vgoyal@redhat.com>,
"Gerd Hoffmann" <kraxel@redhat.com>
Subject: Re: Reuse framebuffer after a kexec (amdgpu / efifb)
Date: Thu, 9 Dec 2021 15:17:51 -0300 [thread overview]
Message-ID: <eaea0143-a961-b83c-3c6c-4d612cd003bc@igalia.com> (raw)
In-Reply-To: <CADnq5_N9ptK4c86LO77YcrF5_M==hket+L7eYjsGCaKbORO=ug@mail.gmail.com>
Thanks again Alex! Some comments inlined below:
On 09/12/2021 15:06, Alex Deucher wrote:
> Not really in a generic way. It's asic and platform specific. In
> addition most modern displays require link training to bring up the
> display, so you can't just save and restore registers.
Oh sure, I understand that. My question is more like: is there a way,
inside amdgpu driver, to save this state before taking
over/overwriting/reprogramming the device? So we could (again, from
inside the amdgpu driver) dump this pre-saved state in the shutdown
handler, for example, having the device in a "pre-OS" state when the new
kexec'ed kernel starts.
>
> The drivers are asic and platform specific. E.g., the driver for
> vangogh is different from renoir is different from skylake, etc. The
> display programming interfaces are asic specific.
Cool, that makes sense! But if you (or anybody here) know some of these
GOP drivers, e.g. for the qemu/qxl device, I'm just curious to
see/understand how complex is the FW driver to just put the
device/screen in a usable state.
Cheers,
Guilherme
WARNING: multiple messages have this Message-ID (diff)
From: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
To: Alex Deucher <alexdeucher@gmail.com>
Cc: "open list:EFIFB FRAMEBUFFER DRIVER"
<linux-fbdev@vger.kernel.org>,
kexec@lists.infradead.org,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
kernel@gpiccoli.net, "Baoquan He" <bhe@redhat.com>,
"Samuel Iglesias Gonsálvez" <siglesias@igalia.com>,
"xinhui pan" <Xinhui.Pan@amd.com>,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
pjones@redhat.com, "Gerd Hoffmann" <kraxel@redhat.com>,
"Deucher, Alexander" <alexander.deucher@amd.com>,
"Dave Young" <dyoung@redhat.com>,
"Christian Koenig" <christian.koenig@amd.com>,
"Vivek Goyal" <vgoyal@redhat.com>
Subject: Re: Reuse framebuffer after a kexec (amdgpu / efifb)
Date: Thu, 9 Dec 2021 15:17:51 -0300 [thread overview]
Message-ID: <eaea0143-a961-b83c-3c6c-4d612cd003bc@igalia.com> (raw)
In-Reply-To: <CADnq5_N9ptK4c86LO77YcrF5_M==hket+L7eYjsGCaKbORO=ug@mail.gmail.com>
Thanks again Alex! Some comments inlined below:
On 09/12/2021 15:06, Alex Deucher wrote:
> Not really in a generic way. It's asic and platform specific. In
> addition most modern displays require link training to bring up the
> display, so you can't just save and restore registers.
Oh sure, I understand that. My question is more like: is there a way,
inside amdgpu driver, to save this state before taking
over/overwriting/reprogramming the device? So we could (again, from
inside the amdgpu driver) dump this pre-saved state in the shutdown
handler, for example, having the device in a "pre-OS" state when the new
kexec'ed kernel starts.
>
> The drivers are asic and platform specific. E.g., the driver for
> vangogh is different from renoir is different from skylake, etc. The
> display programming interfaces are asic specific.
Cool, that makes sense! But if you (or anybody here) know some of these
GOP drivers, e.g. for the qemu/qxl device, I'm just curious to
see/understand how complex is the FW driver to just put the
device/screen in a usable state.
Cheers,
Guilherme
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kexec@lists.infradead.org
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next prev parent reply other threads:[~2021-12-09 18:18 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 16:00 Reuse framebuffer after a kexec (amdgpu / efifb) Guilherme G. Piccoli
2021-12-09 16:00 ` Guilherme G. Piccoli
2021-12-09 16:00 ` Guilherme G. Piccoli
2021-12-09 16:09 ` Christian König
2021-12-09 16:09 ` Christian König
2021-12-09 16:09 ` Christian König
2021-12-09 17:31 ` Alex Deucher
2021-12-09 17:31 ` Alex Deucher
2021-12-09 17:31 ` Alex Deucher
2021-12-09 17:59 ` Guilherme G. Piccoli
2021-12-09 17:59 ` Guilherme G. Piccoli
2021-12-09 17:59 ` Guilherme G. Piccoli
2021-12-09 18:06 ` Alex Deucher
2021-12-09 18:06 ` Alex Deucher
2021-12-09 18:06 ` Alex Deucher
2021-12-09 18:17 ` Guilherme G. Piccoli [this message]
2021-12-09 18:17 ` Guilherme G. Piccoli
2021-12-09 18:17 ` Guilherme G. Piccoli
2021-12-09 19:20 ` Alex Deucher
2021-12-09 19:20 ` Alex Deucher
2021-12-09 19:20 ` Alex Deucher
2021-12-10 7:19 ` Gerd Hoffmann
2021-12-10 7:19 ` Gerd Hoffmann
2021-12-10 7:19 ` Gerd Hoffmann
2021-12-10 7:19 ` Gerd Hoffmann
2021-12-10 8:24 ` Thomas Zimmermann
2021-12-10 8:24 ` Thomas Zimmermann
2021-12-10 14:08 ` Guilherme G. Piccoli
2021-12-10 14:08 ` Guilherme G. Piccoli
2021-12-10 14:08 ` Guilherme G. Piccoli
2021-12-10 14:16 ` Alex Deucher
2021-12-10 14:16 ` Alex Deucher
2021-12-10 14:16 ` Alex Deucher
2021-12-10 14:25 ` Guilherme G. Piccoli
2021-12-10 14:25 ` Guilherme G. Piccoli
2021-12-10 14:25 ` Guilherme G. Piccoli
2021-12-10 15:13 ` Christian König
2021-12-10 15:13 ` Christian König
2021-12-10 15:13 ` Christian König
2021-12-10 15:24 ` Guilherme G. Piccoli
2021-12-10 15:24 ` Guilherme G. Piccoli
2021-12-10 15:24 ` Guilherme G. Piccoli
2021-12-10 15:32 ` Christian König
2021-12-10 15:32 ` Christian König
2021-12-10 15:32 ` Christian König
2021-12-10 19:11 ` Alex Deucher
2021-12-10 19:11 ` Alex Deucher
2021-12-10 19:11 ` Alex Deucher
2021-12-11 0:54 ` Felix Kuehling
2021-12-11 0:54 ` Felix Kuehling
2021-12-11 0:54 ` Felix Kuehling
2021-12-11 9:20 ` Gerd Hoffmann
2021-12-11 9:20 ` Gerd Hoffmann
2021-12-11 9:20 ` Gerd Hoffmann
2021-12-11 9:20 ` Gerd Hoffmann
2021-12-10 19:05 ` Alex Deucher
2021-12-10 19:05 ` Alex Deucher
2021-12-10 19:05 ` Alex Deucher
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