In some cases the sink can reset itself after it was configured into MST
mode, without the driver noticing the disconnected state. For instance
the reset may happen in the middle of a modeset, or the (long) HPD pulse
generated may be not long enough for the encoder detect handler to
observe the HPD's deasserted state. In this case the sink's DPCD
register programmed to enable MST will be reset, while the driver still
assumes MST is still enabled. Detect this condition, which will tear
down and recreate/re-enable the MST topology.
v2:
- Add a code comment about adjusting the expected DP_MSTM_CTRL register
value for SST + SideBand. (Suraj, Jani)
- Print a debug message about detecting the link reset. (Jani)
- Verify the DPCD MST state only if it wasn't already determined that
the sink is disconnected.
Cc: stable(a)vger.kernel.org
Cc: Jani Nikula <jani.nikula(a)intel.com>
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/11195
Reviewed-by: Suraj Kandpal <suraj.kandpal(a)intel.com> (v1)
Signed-off-by: Imre Deak <imre.deak(a)intel.com>
---
drivers/gpu/drm/i915/display/intel_dp.c | 12 +++++++
drivers/gpu/drm/i915/display/intel_dp_mst.c | 40 +++++++++++++++++++++
drivers/gpu/drm/i915/display/intel_dp_mst.h | 1 +
3 files changed, 53 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 6a0c7ae654f40..789c2f78826d0 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5999,6 +5999,18 @@ intel_dp_detect(struct drm_connector *connector,
else
status = connector_status_disconnected;
+ if (status != connector_status_disconnected &&
+ !intel_dp_mst_verify_dpcd_state(intel_dp))
+ /*
+ * This requires retrying detection for instance to re-enable
+ * the MST mode that got reset via a long HPD pulse. The retry
+ * will happen either via the hotplug handler's retry logic,
+ * ensured by setting the connector here to SST/disconnected,
+ * or via a userspace connector probing in response to the
+ * hotplug uevent sent when removing the MST connectors.
+ */
+ status = connector_status_disconnected;
+
if (status == connector_status_disconnected) {
memset(&intel_dp->compliance, 0, sizeof(intel_dp->compliance));
memset(intel_connector->dp.dsc_dpcd, 0, sizeof(intel_connector->dp.dsc_dpcd));
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 45d2230d1801b..15541932b809e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -2062,3 +2062,43 @@ void intel_dp_mst_prepare_probe(struct intel_dp *intel_dp)
intel_mst_set_probed_link_params(intel_dp, link_rate, lane_count);
}
+
+/*
+ * intel_dp_mst_verify_dpcd_state - verify the MST SW enabled state wrt. the DPCD
+ * @intel_dp: DP port object
+ *
+ * Verify if @intel_dp's MST enabled SW state matches the corresponding DPCD
+ * state. A long HPD pulse - not long enough to be detected as a disconnected
+ * state - could've reset the DPCD state, which requires tearing
+ * down/recreating the MST topology.
+ *
+ * Returns %true if the SW MST enabled and DPCD states match, %false
+ * otherwise.
+ */
+bool intel_dp_mst_verify_dpcd_state(struct intel_dp *intel_dp)
+{
+ struct intel_display *display = to_intel_display(intel_dp);
+ struct intel_connector *connector = intel_dp->attached_connector;
+ struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
+ struct intel_encoder *encoder = &dig_port->base;
+ int ret;
+ u8 val;
+
+ if (!intel_dp->is_mst)
+ return true;
+
+ ret = drm_dp_dpcd_readb(intel_dp->mst_mgr.aux, DP_MSTM_CTRL, &val);
+
+ /* Adjust the expected register value for SST + SideBand. */
+ if (ret < 0 || val != (DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC)) {
+ drm_dbg_kms(display->drm,
+ "[CONNECTOR:%d:%s][ENCODER:%d:%s] MST mode got reset, removing topology (ret=%d, ctrl=0x%02x)\n",
+ connector->base.base.id, connector->base.name,
+ encoder->base.base.id, encoder->base.name,
+ ret, val);
+
+ return false;
+ }
+
+ return true;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.h b/drivers/gpu/drm/i915/display/intel_dp_mst.h
index fba76454fa67f..8343804ce3f8d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.h
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.h
@@ -28,5 +28,6 @@ int intel_dp_mst_atomic_check_link(struct intel_atomic_state *state,
bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state,
struct intel_crtc *crtc);
void intel_dp_mst_prepare_probe(struct intel_dp *intel_dp);
+bool intel_dp_mst_verify_dpcd_state(struct intel_dp *intel_dp);
#endif /* __INTEL_DP_MST_H__ */
--
2.44.2
Currently, the behavior of zswap.writeback wrt.
the cgroup hierarchy seems a bit odd. Unlike zswap.max,
it doesn't honor the value from parent cgroups. This
surfaced when people tried to globally disable zswap writeback,
i.e. reserve physical swap space only for hibernation [1] -
disabling zswap.writeback only for the root cgroup results
in subcgroups with zswap.writeback=1 still performing writeback.
The inconsistency became more noticeable after I introduced
the MemoryZSwapWriteback= systemd unit setting [2] for
controlling the knob. The patch assumed that the kernel would
enforce the value of parent cgroups. It could probably be
workarounded from systemd's side, by going up the slice unit
tree and inheriting the value. Yet I think it's more sensible
to make it behave consistently with zswap.max and friends.
[1] https://wiki.archlinux.org/title/Power_management/Suspend_and_hibernate#Dis…
[2] https://github.com/systemd/systemd/pull/31734
Changes in v3:
- Additionally drop inheritance of zswap.writeback setting
on cgroup creation, which is no longer needed
Link to v2: https://lore.kernel.org/linux-kernel/20240816144344.18135-1-me@yhndnzj.com/
Changes in v2:
- Actually base on latest tree (is_zswap_enabled() -> zswap_is_enabled())
- Update Documentation/admin-guide/cgroup-v2.rst to reflect the change
Link to v1: https://lore.kernel.org/linux-kernel/20240814171800.23558-1-me@yhndnzj.com/
Cc: Nhat Pham <nphamcs(a)gmail.com>
Cc: Yosry Ahmed <yosryahmed(a)google.com>
Cc: Johannes Weiner <hannes(a)cmpxchg.org>
Cc: Andrew Morton <akpm(a)linux-foundation.org>
Cc: Michal Koutný <mkoutny(a)suse.com>
Fixes: 501a06fe8e4c ("zswap: memcontrol: implement zswap writeback disabling")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Mike Yuan <me(a)yhndnzj.com>
Reviewed-by: Nhat Pham <nphamcs(a)gmail.com>
Acked-by: Yosry Ahmed <yosryahmed(a)google.com>
---
Documentation/admin-guide/cgroup-v2.rst | 7 ++++---
mm/memcontrol.c | 12 +++++++++---
2 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 86311c2907cd..95c18bc17083 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1717,9 +1717,10 @@ The following nested keys are defined.
entries fault back in or are written out to disk.
memory.zswap.writeback
- A read-write single value file. The default value is "1". The
- initial value of the root cgroup is 1, and when a new cgroup is
- created, it inherits the current value of its parent.
+ A read-write single value file. The default value is "1".
+ Note that this setting is hierarchical, i.e. the writeback would be
+ implicitly disabled for child cgroups if the upper hierarchy
+ does so.
When this is set to 0, all swapping attempts to swapping devices
are disabled. This included both zswap writebacks, and swapping due
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f29157288b7d..d563fb515766 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3613,8 +3613,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
memcg1_soft_limit_reset(memcg);
#ifdef CONFIG_ZSWAP
memcg->zswap_max = PAGE_COUNTER_MAX;
- WRITE_ONCE(memcg->zswap_writeback,
- !parent || READ_ONCE(parent->zswap_writeback));
+ WRITE_ONCE(memcg->zswap_writeback, true);
#endif
page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
if (parent) {
@@ -5320,7 +5319,14 @@ void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size)
bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg)
{
/* if zswap is disabled, do not block pages going to the swapping device */
- return !zswap_is_enabled() || !memcg || READ_ONCE(memcg->zswap_writeback);
+ if (!zswap_is_enabled())
+ return true;
+
+ for (; memcg; memcg = parent_mem_cgroup(memcg))
+ if (!READ_ONCE(memcg->zswap_writeback))
+ return false;
+
+ return true;
}
static u64 zswap_current_read(struct cgroup_subsys_state *css,
base-commit: 47ac09b91befbb6a235ab620c32af719f8208399
--
2.46.0
pinmux_generic_get_function() can return NULL and the pointer 'function'
was dereferenced without checking against NULL. Add checking of pointer
'function' in pcs_get_function().
Found by code review.
Cc: stable(a)vger.kernel.org
Fixes: 571aec4df5b7 ("pinctrl: single: Use generic pinmux helpers for managing functions")
Signed-off-by: Ma Ke <make24(a)iscas.ac.cn>
---
drivers/pinctrl/pinctrl-single.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
index 4c6bfabb6bd7..4da3c3f422b6 100644
--- a/drivers/pinctrl/pinctrl-single.c
+++ b/drivers/pinctrl/pinctrl-single.c
@@ -345,6 +345,8 @@ static int pcs_get_function(struct pinctrl_dev *pctldev, unsigned pin,
return -ENOTSUPP;
fselector = setting->func;
function = pinmux_generic_get_function(pctldev, fselector);
+ if (!function)
+ return -EINVAL;
*func = function->data;
if (!(*func)) {
dev_err(pcs->dev, "%s could not find function%i\n",
--
2.25.1
From: Oliver Neukum <oneukum(a)suse.com>
[ Upstream commit e5876b088ba03a62124266fa20d00e65533c7269 ]
ipheth_sndbulk_callback() can submit carrier_work
as a part of its error handling. That means that
the driver must make sure that the work is cancelled
after it has made sure that no more URB can terminate
with an error condition.
Hence the order of actions in ipheth_close() needs
to be inverted.
Signed-off-by: Oliver Neukum <oneukum(a)suse.com>
Signed-off-by: Foster Snowhill <forst(a)pen.gy>
Tested-by: Georgi Valkov <gvalkov(a)gmail.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
drivers/net/usb/ipheth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c
index cea005cc7b2ab..c762335587a43 100644
--- a/drivers/net/usb/ipheth.c
+++ b/drivers/net/usb/ipheth.c
@@ -407,8 +407,8 @@ static int ipheth_close(struct net_device *net)
{
struct ipheth_device *dev = netdev_priv(net);
- cancel_delayed_work_sync(&dev->carrier_work);
netif_stop_queue(net);
+ cancel_delayed_work_sync(&dev->carrier_work);
return 0;
}
--
2.43.0
From: Oliver Neukum <oneukum(a)suse.com>
[ Upstream commit e5876b088ba03a62124266fa20d00e65533c7269 ]
ipheth_sndbulk_callback() can submit carrier_work
as a part of its error handling. That means that
the driver must make sure that the work is cancelled
after it has made sure that no more URB can terminate
with an error condition.
Hence the order of actions in ipheth_close() needs
to be inverted.
Signed-off-by: Oliver Neukum <oneukum(a)suse.com>
Signed-off-by: Foster Snowhill <forst(a)pen.gy>
Tested-by: Georgi Valkov <gvalkov(a)gmail.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
drivers/net/usb/ipheth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c
index 73ad78f47763c..7814856636907 100644
--- a/drivers/net/usb/ipheth.c
+++ b/drivers/net/usb/ipheth.c
@@ -353,8 +353,8 @@ static int ipheth_close(struct net_device *net)
{
struct ipheth_device *dev = netdev_priv(net);
- cancel_delayed_work_sync(&dev->carrier_work);
netif_stop_queue(net);
+ cancel_delayed_work_sync(&dev->carrier_work);
return 0;
}
--
2.43.0
From: Oliver Neukum <oneukum(a)suse.com>
[ Upstream commit e5876b088ba03a62124266fa20d00e65533c7269 ]
ipheth_sndbulk_callback() can submit carrier_work
as a part of its error handling. That means that
the driver must make sure that the work is cancelled
after it has made sure that no more URB can terminate
with an error condition.
Hence the order of actions in ipheth_close() needs
to be inverted.
Signed-off-by: Oliver Neukum <oneukum(a)suse.com>
Signed-off-by: Foster Snowhill <forst(a)pen.gy>
Tested-by: Georgi Valkov <gvalkov(a)gmail.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
drivers/net/usb/ipheth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c
index 06d9f19ca142a..0774d753dd316 100644
--- a/drivers/net/usb/ipheth.c
+++ b/drivers/net/usb/ipheth.c
@@ -353,8 +353,8 @@ static int ipheth_close(struct net_device *net)
{
struct ipheth_device *dev = netdev_priv(net);
- cancel_delayed_work_sync(&dev->carrier_work);
netif_stop_queue(net);
+ cancel_delayed_work_sync(&dev->carrier_work);
return 0;
}
--
2.43.0
From: Oliver Neukum <oneukum(a)suse.com>
[ Upstream commit e5876b088ba03a62124266fa20d00e65533c7269 ]
ipheth_sndbulk_callback() can submit carrier_work
as a part of its error handling. That means that
the driver must make sure that the work is cancelled
after it has made sure that no more URB can terminate
with an error condition.
Hence the order of actions in ipheth_close() needs
to be inverted.
Signed-off-by: Oliver Neukum <oneukum(a)suse.com>
Signed-off-by: Foster Snowhill <forst(a)pen.gy>
Tested-by: Georgi Valkov <gvalkov(a)gmail.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
drivers/net/usb/ipheth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c
index d56e276e4d805..4485388dcff2e 100644
--- a/drivers/net/usb/ipheth.c
+++ b/drivers/net/usb/ipheth.c
@@ -353,8 +353,8 @@ static int ipheth_close(struct net_device *net)
{
struct ipheth_device *dev = netdev_priv(net);
- cancel_delayed_work_sync(&dev->carrier_work);
netif_stop_queue(net);
+ cancel_delayed_work_sync(&dev->carrier_work);
return 0;
}
--
2.43.0