From 26b1d3b527e7bf3e24b814d617866ac5199ce68d Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 5 Sep 2019 20:53:18 +0200 Subject: drm/atomic: Take the atomic toys away from X MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The -modesetting ddx has a totally broken idea of how atomic works: - doesn't disable old connectors, assuming they get auto-disable like with the legacy setcrtc - assumes ASYNC_FLIP is wired through for the atomic ioctl - not a single call to TEST_ONLY Iow the implementation is a 1:1 translation of legacy ioctls to atomic, which is a) broken b) pointless. We already have bugs in both i915 and amdgpu-DC where this prevents us from enabling neat features. If anyone ever cares about atomic in X we can easily add a new atomic level (req->value == 2) for X to get back the shiny toys. Since these broken versions of -modesetting have been shipping, there's really no other way to get out of this bind. v2: - add an informational dmesg output (Rob, Ajax) - reorder after the DRIVER_ATOMIC check to avoid useless noise (Ilia) - allow req->value > 2 so that X can do another attempt at atomic in the future v3: Go with paranoid, insist that the X should be first (suggested by Rob) Cc: Ilia Mirkin References: https://gitlab.freedesktop.org/xorg/xserver/issues/629 References: https://gitlab.freedesktop.org/xorg/xserver/merge_requests/180 References: abbc0697d5fb ("drm/fb: revert the i915 Actually configure untiled displays from master") Cc: Maarten Lankhorst Reviewed-by: Maarten Lankhorst (v1) Reviewed-by: Nicholas Kazlauskas (v1) Cc: Michel Dänzer Cc: Alex Deucher Cc: Adam Jackson Acked-by: Adam Jackson Cc: Sean Paul Cc: David Airlie Cc: Rob Clark Acked-by: Rob Clark Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20190905185318.31363-1-daniel.vetter@ffwll.ch --- drivers/gpu/drm/drm_ioctl.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index f675a3bb2c88..fcd728d7cf72 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -336,7 +336,12 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv) case DRM_CLIENT_CAP_ATOMIC: if (!drm_core_check_feature(dev, DRIVER_ATOMIC)) return -EOPNOTSUPP; - if (req->value > 1) + /* The modesetting DDX has a totally broken idea of atomic. */ + if (current->comm[0] == 'X' && req->value == 1) { + pr_info("broken atomic modeset userspace detected, disabling atomic\n"); + return -EOPNOTSUPP; + } + if (req->value > 2) return -EINVAL; file_priv->atomic = req->value; file_priv->universal_planes = req->value; -- cgit v1.2.3