From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Wed, 2 Aug 2017 13:56:03 +0200
Subject: drm: Only lastclose on unload for legacy drivers
Git-commit: 2e45eeac7c1f80a90768e667545591a1e25ff288
Patch-mainline: v4.14-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
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
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/drm_drv.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -860,7 +860,8 @@ void drm_dev_unregister(struct drm_devic
{
struct drm_map_list *r_list, *list_temp;
- drm_lastclose(dev);
+ if (drm_core_check_feature(dev, DRIVER_LEGACY))
+ drm_lastclose(dev);
dev->registered = false;