From: Sidong Yang <[email protected]>

[ Upstream commit 05ca530268a9d0ab3547e7b288635e35990a77c4 ]

This patch avoid the warning in vkms_get_vblank_timestamp when vblanks
aren't enabled. When running igt test kms_cursor_crc just after vkms
module, the warning raised like below. Initial value of vblank time is
zero and hrtimer.node.expires is also zero if vblank aren't enabled
before. vkms module isn't real hardware but just virtual hardware
module. so vkms can't generate a resonable timestamp when hrtimer is
off. it's best to grab the current time.

[106444.464503] [IGT] kms_cursor_crc: starting subtest pipe-A-cursor-size-change
[106444.471475] WARNING: CPU: 0 PID: 10109 at
vkms_get_vblank_timestamp+0x42/0x50 [vkms]
[106444.471511] CPU: 0 PID: 10109 Comm: kms_cursor_crc Tainted: G        W  OE
5.9.0-rc1+ #6
[106444.471514] RIP: 0010:vkms_get_vblank_timestamp+0x42/0x50 [vkms]
[106444.471528] Call Trace:
[106444.471551]  drm_get_last_vbltimestamp+0xb9/0xd0 [drm]
[106444.471566]  drm_reset_vblank_timestamp+0x63/0xe0 [drm]
[106444.471579]  drm_crtc_vblank_on+0x85/0x150 [drm]
[106444.471582]  vkms_crtc_atomic_enable+0xe/0x10 [vkms]
[106444.471592]  drm_atomic_helper_commit_modeset_enables+0x1db/0x230
[drm_kms_helper]
[106444.471594]  vkms_atomic_commit_tail+0x38/0xc0 [vkms]
[106444.471601]  commit_tail+0x97/0x130 [drm_kms_helper]
[106444.471608]  drm_atomic_helper_commit+0x117/0x140 [drm_kms_helper]
[106444.471622]  drm_atomic_commit+0x4a/0x50 [drm]
[106444.471629]  drm_atomic_helper_set_config+0x63/0xb0 [drm_kms_helper]
[106444.471642]  drm_mode_setcrtc+0x1d9/0x7b0 [drm]
[106444.471654]  ? drm_mode_getcrtc+0x1a0/0x1a0 [drm]
[106444.471666]  drm_ioctl_kernel+0xb6/0x100 [drm]
[106444.471677]  drm_ioctl+0x3ad/0x470 [drm]
[106444.471688]  ? drm_mode_getcrtc+0x1a0/0x1a0 [drm]
[106444.471692]  ? tomoyo_file_ioctl+0x19/0x20
[106444.471694]  __x64_sys_ioctl+0x96/0xd0
[106444.471697]  do_syscall_64+0x37/0x80
[106444.471699]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Cc: Daniel Vetter <[email protected]>
Cc: Rodrigo Siqueira <[email protected]>
Cc: Haneen Mohammed <[email protected]>
Cc: Melissa Wen <[email protected]>

Signed-off-by: Sidong Yang <[email protected]>
Reviewed-by: Melissa Wen <[email protected]>
Signed-off-by: Rodrigo Siqueira <[email protected]>
Link: 
https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
---
 drivers/gpu/drm/vkms/vkms_crtc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index ac85e17428f88..09c012d54d58f 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -86,6 +86,11 @@ static bool vkms_get_vblank_timestamp(struct drm_crtc *crtc,
        struct vkms_output *output = &vkmsdev->output;
        struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 
+       if (!READ_ONCE(vblank->enabled)) {
+               *vblank_time = ktime_get();
+               return true;
+       }
+
        *vblank_time = READ_ONCE(output->vblank_hrtimer.node.expires);
 
        if (WARN_ON(*vblank_time == vblank->time))
-- 
2.25.1

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