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Daniel Vetter 2e45eeac7c drm: Only lastclose on unload for legacy drivers
The only thing modern drivers are supposed to do in lastclose is
restore the fb emulation state. Which is entirely optional, and
there's really no reason to do that. So restrict it to legacy drivers
(where the driver cleanup essentially happens in lastclose).

This will also allow us to share the unregister function with
drm_dev_unplug().

Quoting my reply to Alex on dri-devel:
On Thu, Aug 3, 2017 at 1:17 AM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> On Wed, Aug 2, 2017 at 10:50 PM, Alex Deucher <alexdeucher@gmail.com> wrote:
>> On Wed, Aug 2, 2017 at 7:56 AM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>>> The only thing modern drivers are supposed to do in lastclose is
>>> restore the fb emulation state. Which is entirely optional, and
>>> there's really no reason to do that. So restrict it to legacy drivers
>>> (where the driver cleanup essentially happens in lastclose).
>>
>> vga_switcheroo_process_delayed_switch() gets called in lastclose.
>> Won't that need to get moved elsewhere for this to work?
>
> Hm right, I forgot the lazy way to do runtime pm by keeping the device
> alive as long as anyone has an open fd for it ... This shouldn't be a
> problem, since you need to unregister from vgaswitcheroo anyway on
> unload. Maybe that blows up, I'll check the code and augment the patch
> as needed.

So I think there's 3 cases:
- Trying to unload the module. You can't do that while anyone has the
fd still open, so lastclose is guaranteeed to run.
- Forcefully unbinding the driver through sysfs. Not any better, since
the can_switch stuff checks for the open count, and so will delay the
delayed switch no matter what.
- Actual hotremoval: a) not implemented since none of the drivers
taking part in vgaswitcheroo correctly unplug the drm device and b)
you can't hotremove a chip from a laptop.

v2: Extend commit message with m-l discussion.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170802115604.12734-4-daniel.vetter@ffwll.ch
2017-08-11 10:48:12 +02:00
arch Linux 4.13-rc2 2017-07-27 08:15:43 +10:00
block bfq: dispatch request to prevent queue stalling after the request completion 2017-07-12 08:32:04 -06:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-07-14 22:49:50 -07:00
Documentation drm: todo: Avoid accidental crossreferences 2017-07-31 16:03:53 +02:00
drivers drm: Only lastclose on unload for legacy drivers 2017-08-11 10:48:12 +02:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs NFS client bugfixes for 4.13 2017-07-21 16:26:01 -07:00
include drm: Document device unplug infrastructure 2017-08-11 10:48:03 +02:00
init random: do not ignore early device randomness 2017-07-12 16:26:00 -07:00
ipc ipc/util.h: update documentation for ipc_getref() and ipc_putref() 2017-07-12 16:26:02 -07:00
kernel Three minor updates 2017-07-21 13:59:51 -07:00
lib Add wait_for_random_bytes() and get_random_*_wait() functions so that 2017-07-15 12:44:02 -07:00
mm Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-15 12:00:42 -07:00
net NFS client bugfixes for 4.13 2017-07-21 16:26:01 -07:00
samples Merge branch 'akpm' (patches from Andrew) 2017-07-13 12:38:49 -07:00
scripts Properly alphabetize MAINTAINERS file 2017-07-23 16:06:21 -07:00
security Now that IPC and other changes have landed, enable manual markings for 2017-07-19 08:55:18 -07:00
sound sound fixes for 4.13-rc1 2017-07-14 12:44:00 -07:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-21 11:12:48 -07:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Second batch of KVM updates for v4.13 2017-07-15 10:18:16 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Linux 4.13-rc2 2017-07-27 08:15:43 +10:00
Makefile Linux 4.13-rc2 2017-07-23 16:15:17 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.