To make sure that the MCDE is in a reasonable state during
set-up, perform a reset by power cycling the block by dropping
the on-chip regulator reference after probe. The display
subsystem (DSS) has no dedicated reset line so dropping
the EPOD regulator is the only real way of resetting it.

We introduce code to enable and disable the regulator in
the display enable/disable callbacks.

We move the generic MCDE setup such as muxing of DPI
signals and masking of interrupts to the display
handling.

When we drop the power to the whole display subsystem, not
only MCDE but also the DSI links lose their state. Therefore
we move the DSI block reset and hardware initialization
code to the mcde_dsi_bridge_pre_enable() callback so this
happens every time we start up the bridge, as we may have
lost the power.

We move the final disablement of the interrupts and
clocks to the mcde_dsi_bridge_post_disable() callback
rather than have it in the mcde_dsi_bridge_disable()
callback, as some control messages may still be sent
over the DSI host after the bridge has been shut down.

This (together with a patch for the corresponding
panel) makes the Samsung GT-S7710 successfully disable
and re-enable its display, cutting all power while
disabled and re-initializing the hardware when coming
back up.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: newbytee@protonmail.com
Cc: Stephan Gerhold <stephan@gerhold.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200808223122.1492124-3-linus.walleij@linaro.org

It is possible to set a flag in the struct mipi_dsi_device
so the panel is handled in low power (LP) mode. Some displays
only support this mode and it is also good for testing.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: newbytee@protonmail.com
Cc: Stephan Gerhold <stephan@gerhold.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200808223122.1492124-2-linus.walleij@linaro.org

The pixel fetcher FIFO depth was just hardcoded to 48
which works fine as long as the framebuffer is 32BPP
and the DSI output is RGB888.

We will need more elaborate handling for some buffer
formats and displays, so start to improve this function
by setting reasonable defaults for 32, 24 and 16 BPP
framebuffers.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: newbytee@protonmail.com
Cc: Stephan Gerhold <stephan@gerhold.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200808223122.1492124-1-linus.walleij@linaro.org

Revamp the way that the flow of data to the display is
defined.

I realized that the hardware supports something like
5 different modes of flow: oneshot, command with TE IRQ,
command with BTA (bus turn around) and TE IRQ, video
with TE IRQ and video without TE IRQ instead synchronizing
to the output of the MCDE DSI formatter.

Like before the selection of the type of flow is done
from the DSI driver when we attach it to the MCDE and we
get to know what the display wants.

The new video mode synchronization method from the MCDE DSI
formatter is used on some upstream devices such as Golden.
This is the new default for video mode: stateless panels
do not as a rule generate TE IRQs.

Another semantic change is that we stop sending
a TE request before every command when sending data to
a display in command mode: this should only be explicitly
requested when using BTA, according to the vendor driver.

This has been tested and works fine with the command mode
displays I have. (All that are supported upstream.)

Reported-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
Cc: Stephan Gerhold <stephan@gerhold.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200729090915.252730-2-linus.walleij@linaro.org

The function mcde_display_send_one_frame() has a historical
name that stems from being implemented when the driver
only supported single frame updates.

Rename it mcde_start_flow() so that it reflects the current
usage.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200729090915.252730-1-linus.walleij@linaro.org

Add missing include to fix build error:
hibmc_drm_drv.c:385:1: warning: data definition has no type or storage
class [enabled by default]
hibmc_drm_drv.c:385:1: error: type defaults to ‘int’ in declaration
of ‘module_init’ [-Werror=implicit-int]
hibmc_drm_drv.c:385:1: warning: parameter names (without types) in function
of ‘module_exit’ [-Werror=implicit-int]
hibmc_drm_drv.c:385:292:1: warning: parameter names (without types) in
function declaration [enabled by default]

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1597289955-27381-1-git-send-email-tiantao6@hisilicon.com

Add very basic driver for Toshiba TC358762 DSI-to-DPI bridge, derived
from tc358764 driver and panel-raspberrypi-touchscreen. This driver is
meant to replace the panel-raspberrypi-touchscreen too, as the bridge
connection can be described in DT too.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: dri-devel@lists.freedesktop.org
Cc: Eric Anholt <eric@anholt.net>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: devicetree@vger.kernel.org
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam.ravnborg@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200809105705.6334-2-marex@denx.de

Add DT bindings for Toshiba TC358762 DSI-to-DPI bridge, this
one is used in the Raspberry Pi 7" touchscreen display unit.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: dri-devel@lists.freedesktop.org
Cc: Eric Anholt <eric@anholt.net>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Sam Ravnborg <sam.ravnborg@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200809105705.6334-1-marex@denx.de

Backmerging drm-next into drm-misc-next for nouveau and panel updates.
Resolves a conflict between ttm and nouveau, where struct ttm_mem_res got
renamed to struct ttm_resource.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

The object flags created in radeon_ttm_placement_from_domain take care that
we use the correct caching for AGP, this is just superflous.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/384336/?series=80346&rev=1

This is a separate object we work within TTM.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/384338/?series=80346&rev=1

The names get/put are associated with reference counting
in the Linux kernel, use alloc/free instead.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/384340/?series=80346&rev=1

The memory used to be allocated with devres helpers and released
automatically. In rare circumstances, the memory's release could
have happened before the DRM device got released, which would have
caused memory corruption of some kind. Now we're embedding the data
structures in struct hibmc_drm_private. The whole release problem
has been resolved, because struct hibmc_drm_private is allocated
with drmm_kzalloc and always released with the DRM device.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1597218179-3938-3-git-send-email-tiantao6@hisilicon.com

Remove some unused include statements.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1597218179-3938-2-git-send-email-tiantao6@hisilicon.com

This reverts commit 2ddef176

.

As it turned out VMWGFX needs a much wider audit to fix this.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200811092400.188124-1-christian.koenig@amd.com

The drm_mode_config_reset patches are very important fixing a recently
introduced kernel crash, the others fix various older issues which are
a bit less serious in practice.

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: "Roland Scheidegger (VMware)" <rscheidegger.oss@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200812005941.19465-1-rscheidegger.oss@gmail.com

In order to successfully read ID of the MTP panel the
panel MTP control page must be unlocked. Previously
this wasn't encountered because in the setup with this
panel the power wasn't ever really dropped. When power
gets dropped from the panel, MTP needs to be unlocked.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: newbytee@protonmail.com
Cc: Stephan Gerhold <stephan@gerhold.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200808224322.1507713-1-linus.walleij@linaro.org

Since DP-specific information is stored in driver's structures, every
driver needs to implement subconnector property by itself. Display
Core already has the subconnector information, we only need to
expose it through DRM property.

v2:rebase

v3: renamed a function call

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: David (ChunMing) Zhou <David1.Zhou@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Jeevan B <jeevan.b@intel.com>
Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
Tested-by: Oleg Vasilev <oleg.vasilev@intel.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1587732655-17544-5-git-send-email-jeevan.b@intel.com

Since DP-specific information is stored in driver's structures, every
driver needs to implement subconnector property by itself.

v2: rebase

v3: renamed a function call

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: David (ChunMing) Zhou <David1.Zhou@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Jeevan B <jeevan.b@intel.com>
Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1587732655-17544-4-git-send-email-jeevan.b@intel.com

Since DP-specific information is stored in driver's structures, every
driver needs to implement subconnector property by itself.

v2: updates to match previous commit changes

v3: rebase

v4: renamed a function call

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Signed-off-by: Jeevan B <jeevan.b@intel.com>
Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com> #and acked for merging
Tested-by: Oleg Vasilev <oleg.vasilev@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1587732655-17544-2-git-send-email-jeevan.b@intel.com

Currently, downstream port type is only reported in debugfs. This
information should be considered important since it reflects the actual
physical connector type. Some userspace (e.g. window compositors)
may want to show this info to a user.

The 'subconnector' property is already utilized for DVI-I and TV-out for
reporting connector subtype.

The initial motivation for this feature came from i2c test [1].
It is supposed to be skipped on VGA connectors, but it cannot
detect VGA over DP and fails instead.

v2:
 - Ville: utilized drm_dp_is_branch()
 - Ville: implement DP 1.0 downstream type info
 - Replaced create_dp_properties with add_dp_subconnector_property
 - Added dp_set_subconnector_property helper

v4:
 - Ville: add DP1.0 best assumption about subconnector
 - Ville: assume DVI is DVI-D
 - Ville: reuse Writeback enum value for Virtual subconnector
 - Renamed #defines: HDMI -> HDMIA, DP -> DisplayPort

v5: rebase

v6:
 - Jani Nikula: renamed a function name
 - Jani Nikula: addressed the issues with documentation

[1]: https://bugs.freedesktop.org/show_bug.cgi?id=104097



Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Signed-off-by: Jeevan B <jeevan.b@intel.com>
Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1587732655-17544-1-git-send-email-jeevan.b@intel.com

amd-drm-fixes-5.9-2020-08-07:

amdgpu:
- Re-add spelling typo fix
- Sienna Cichlid fixes
- Navy Flounder fixes
- DC fixes
- SMU i2c fix
- Power fixes

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Alex Deucher <alexdeucher@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200807222843.3909-1-alexander.deucher@amd.com

 * backmerge from drm-fixes at v5.8-rc7
 * add orientation quirk for ASUS T103HAF
 * drm/omap: force runtime PM suspend on system suspend
 * drm/tidss: fix modeset init for DPI panels
 * re-added docs for drm_gem_flink_ioctl()
 * ttm: fix page-offset calculation within TTM

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20200804125510.GA29670@linux-uq9g

I need to backmerge 5.8 as I've got a bunch of fixes sitting
on an rc7 base that I want to land.

Signed-off-by: Dave Airlie <airlied@redhat.com>

I fixed the init path, but missed the cleanup path.

Fixes: e0830704

 ("drm/vmwgfx: takedown vram manager")
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200810054110.4192239-1-airlied@gmail.com

There is a spelling mistake in a DRM_ERROR message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Roland Scheidegger <sroland@vmware.com>

There is a spelling mistake in a DRM_ERROR message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Roland Scheidegger <sroland@vmware.com>

Same problem as in stdu, same fix.

Fixes: 51f644b4

 ("drm/atomic-helper: reset vblank on crtc reset")
Acked-by: Charmaine Lee <charmainel@vmware.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Signed-off-by: Roland Scheidegger <sroland@vmware.com>

Same problem as in stdu, same fix.

Fixes: 51f644b4

 ("drm/atomic-helper: reset vblank on crtc reset")
Acked-by: Charmaine Lee <charmainel@vmware.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Signed-off-by: Roland Scheidegger <sroland@vmware.com>

When converting to atomic the state reset was done by directly calling
the functions, and before the modeset object was fully initialized.
This means the various ->dev pointers weren't set up.

After

commit 51f644b4
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Jun 12 18:00:49 2020 +0200

    drm/atomic-helper: reset vblank on crtc reset

this started to oops because now we're trying to derefence
drm_crtc->dev. Fix this up by entirely switching over to
drm_mode_config_reset, called once everything is set up.

Fixes: 51f644b4

 ("drm/atomic-helper: reset vblank on crtc reset")
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Tested-by: Roland Scheidegger <sroland@vmware.com>
Signed-off-by: Roland Scheidegger <sroland@vmware.com>

These if statements are supposed to be true if we ended the
list_for_each_entry() loops without hitting a break statement but they
don't work.

In the first loop, we increment "i" after the "if (i == unit)" condition
so we don't necessarily know that "i" is not equal to unit at the end of
the loop.

In the second loop we exit when mode is not pointing to a valid
drm_display_mode struct so it doesn't make sense to check "mode->type".

Fixes: a278724a

 ("drm/vmwgfx: Implement fbdev on kms v2")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Signed-off-by: Roland Scheidegger <sroland@vmware.com>

The "entry" pointer is an offset from the list head and it doesn't
point to a valid vmw_legacy_display_unit struct.  Presumably the
intent was to point to the last entry.

Also the "i++" wasn't used so I have removed that as well.

Fixes: d7e1958d

 ("drm/vmwgfx: Support older hardware.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Signed-off-by: Roland Scheidegger <sroland@vmware.com>

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

This code was detected with the help of Coccinelle and, audited and
fixed manually.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Roland Scheidegger <sroland@vmware.com>

Merge tag 'drm-misc-next-fixes-2020-08-05' of git://anongit.freedesktop.org/drm/drm-misc

 into drm-next

drm-misc-next-fixes for v5.9-rc1:
- Fix drm_dp_mst_port refcount leaks in drm_dp_mst_allocate_vcpi
- Fix a fbcon OOB read in fbdev, found by syzbot.
- Mark vga_tryget static as it's not used elsewhere.
- Small fixes to xlnx.
- Remove null check for kfree in drm_dev_release.
- Fix DRM_FORMAT_MOD_AMLOGIC_FBC definition.
- Fix mode initialization in omap_connector_mode_valid().

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b2043dad-f118-bd19-54a6-f23bf6264007@linux.intel.com

This driver is tested with two panels individually with Apq8016-IFC6309 board
https://www.inforcecomputing.com/products/single-board-computers-sbc/qualcomm-snapdragon-410-inforce-6309-micro-sbc



1. 1366x768@60 auo,b101xtn01 data-mapping = "jeida-24"
2. 800x480@60 innolux,at070tn92 data-mapping = "vesa-24"

- power off sequence in proper order
- put_unaligned_be16, put_unaligned_le32 macros used
- static function for mode_valid
- len initialized
- MODE_CLOCK_HIGH handled properly
- bus_formats handled in mode_valid
- GENMASK and FIELD_PREP used
- Kconfig proper indentation
- error handling endpoint data-lanes
- check for bus_formats unsupported
- display_timings naming local variables
- help modified
- ~vsdelay dynamic value set based on the
  calculation of dsi speed, output speed, blanking
- panel->connector_type removed
- dual port implemented
- devm_drm_panel_bridge_add method used instead of panel
  description modified
- regulator enable and disable with proper orders and delays
  as per the spec
- removed drm_connector_status
- added bus_formats
- mdelay to usleep_range
- magic number to macros for CLRSI and mux registers
  description modified
- replaced u32 instead of uint32_t
- updated alphabetic order of headers
- added SPDX identifier license

Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam.ravnborg@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1594388491-15129-2-git-send-email-simhavcs@gmail.com

- license modified to (GPL-2.0-only OR BSD-2-Clause)
- single-link and dual-link lvds description and
  examples are added
- proper indentation
- VESA/JEIDA formats picked from panel-lvds dts
- dsi data-lanes property removed, it will be picked
  from dsi0 ports
- dual-link lvds port added and implemented
- converted from .txt to .yaml

Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sam Ravnborg <sam.ravnborg@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1594388491-15129-1-git-send-email-simhavcs@gmail.com

Get rid of boilerplate code by using module_platform_driver macro
for v3d_drm.

Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200810125931.186456-1-miaoqinglang@huawei.com

When vkms_init() get into out_put, the unregister call of
vkms_device->platform is missing. So add it before return.

Fixes: ac19f140

 ("drm/vkms: Use drmm_add_final_kfree")
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200810130011.187691-1-miaoqinglang@huawei.com

When vgem_init() get into out_put, the unregister call of
vgem_device->platform is missing. So add it before return.

Fixes: 363de9e7

 ("drm/vgem: Use drmm_add_final_kfree")
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200810125942.186637-1-miaoqinglang@huawei.com

VKMS needs vblank interrupts enabled to capture CRC. When vblank is
disabled, tests like kms_cursor_crc and kms_pipe_crc_basic getting stuck
waiting for a capture that will not occur until vkms wakes up. This patch
adds a helper to set composer and ensure that vblank remains enabled as
long as the CRC capture is needed.

It clears the execution of the following kms_cursor_crc subtests:
1. pipe-A-cursor-[size,alpha-opaque, NxN-(on-screen, off-screen, sliding,
random, fast-moving])] - successful when running individually.
2. pipe-A-cursor-dpms passes again
3. pipe-A-cursor-suspend also passes

The issue was initially tracked in the sequential execution of IGT
kms_cursor_crc subtests: when running the test sequence or one of its
subtests twice, the odd execs complete and the pairs get stuck in an
endless wait. In the IGT code, calling a wait_for_vblank on preparing for
CRC capture prevented the busy-wait. But the problem persisted in the
pipe-A-cursor-dpms and -suspend subtests.

Checking the history, the pipe-A-cursor-dpms subtest was successful when,
in vkms_atomic_commit_tail, instead of using the flip_done op, it used
wait_for_vblanks. Another way to prevent blocking was wait_one_vblank when
enabling crtc. However, in both cases, pipe-A-cursor-suspend persisted
blocking in the 2nd start of CRC capture, which may indicate that
something got stuck in the step of CRC setup. Indeed, wait_one_vblank in
the crc setup was able to sync things and free all kms_cursor_crc
subtests. Besides, other alternatives to force enabling vblanks or prevent
disabling them such as calling drm_crtc_put_vblank or modeset_enables
before commit_planes + offdelay = 0, also unlock all subtests executions.

Finally, due to vkms's dependence on vblank interruptions to perform
tasks, this patch uses refcount to ensure that vblanks happen when
enabling composer and while crc capture is needed.

Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>

v2:
- extract a vkms_set_composer helper
- fix vblank refcounting for the disabling case

v3:
- make the vkms_set_composer helper static
- review the credit tags

Co-debugged-by: Sidong Yang <realwakka@gmail.com>
Signed-off-by: Sidong Yang <realwakka@gmail.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: add changelog back in]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200808120900.pudwwrfz44g3rqx7@smtp.gmail.com