From fd5c46b754d4799afda8dcdd6851e0390aa4961a Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Thu, 19 Sep 2019 14:55:23 +0300 Subject: thunderbolt: Read DP IN adapter first two dwords in one go When we discover existing DP tunnels the code checks whether DP IN adapter port is enabled by calling tb_dp_port_is_enabled() before it continues the discovery process. On Light Ridge (gen 1) controller reading only the first dword of the DP IN config space causes subsequent access to the same DP IN port path config space to fail or return invalid data as can be seen in the below splat: thunderbolt 0000:07:00.0: CFG_ERROR(0:d): Invalid config space or offset Call Trace: tb_cfg_read+0xb9/0xd0 __tb_path_deactivate_hop+0x98/0x210 tb_path_activate+0x228/0x7d0 tb_tunnel_restart+0x95/0x200 tb_handle_hotplug+0x30e/0x630 process_one_work+0x1b4/0x340 worker_thread+0x44/0x3d0 kthread+0xeb/0x120 ? process_one_work+0x340/0x340 ? kthread_park+0xa0/0xa0 ret_from_fork+0x1f/0x30 If both DP In adapter config dwords are read in one go the issue does not reproduce. This is likely firmware bug but we can work it around by always reading the two dwords in one go. There should be no harm for other controllers either so can do it unconditionally. Link: https://lkml.org/lkml/2019/8/28/160 Reported-by: Brad Campbell Tested-by: Brad Campbell Signed-off-by: Mika Westerberg --- drivers/thunderbolt/switch.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'drivers') diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index 410bf1bceeee..8e712fbf8233 100644 --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -896,12 +896,13 @@ int tb_dp_port_set_hops(struct tb_port *port, unsigned int video, */ bool tb_dp_port_is_enabled(struct tb_port *port) { - u32 data; + u32 data[2]; - if (tb_port_read(port, &data, TB_CFG_PORT, port->cap_adap, 1)) + if (tb_port_read(port, data, TB_CFG_PORT, port->cap_adap, + ARRAY_SIZE(data))) return false; - return !!(data & (TB_DP_VIDEO_EN | TB_DP_AUX_EN)); + return !!(data[0] & (TB_DP_VIDEO_EN | TB_DP_AUX_EN)); } /** @@ -914,19 +915,21 @@ bool tb_dp_port_is_enabled(struct tb_port *port) */ int tb_dp_port_enable(struct tb_port *port, bool enable) { - u32 data; + u32 data[2]; int ret; - ret = tb_port_read(port, &data, TB_CFG_PORT, port->cap_adap, 1); + ret = tb_port_read(port, data, TB_CFG_PORT, port->cap_adap, + ARRAY_SIZE(data)); if (ret) return ret; if (enable) - data |= TB_DP_VIDEO_EN | TB_DP_AUX_EN; + data[0] |= TB_DP_VIDEO_EN | TB_DP_AUX_EN; else - data &= ~(TB_DP_VIDEO_EN | TB_DP_AUX_EN); + data[0] &= ~(TB_DP_VIDEO_EN | TB_DP_AUX_EN); - return tb_port_write(port, &data, TB_CFG_PORT, port->cap_adap, 1); + return tb_port_write(port, data, TB_CFG_PORT, port->cap_adap, + ARRAY_SIZE(data)); } /* switch utility functions */ -- cgit v1.2.3 From 6f6709734274aef75058356e029d5e8f86d0d53b Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Thu, 19 Sep 2019 15:28:58 +0300 Subject: thunderbolt: Fix lockdep circular locking depedency warning When lockdep is enabled, plugging Thunderbolt dock on Dominik's laptop triggers following splat: ====================================================== WARNING: possible circular locking dependency detected 5.3.0-rc6+ #1 Tainted: G T ------------------------------------------------------ pool-/usr/lib/b/1258 is trying to acquire lock: 000000005ab0ad43 (pci_rescan_remove_lock){+.+.}, at: authorized_store+0xe8/0x210 but task is already holding lock: 00000000bfb796b5 (&tb->lock){+.+.}, at: authorized_store+0x7c/0x210 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&tb->lock){+.+.}: __mutex_lock+0xac/0x9a0 tb_domain_add+0x2d/0x130 nhi_probe+0x1dd/0x330 pci_device_probe+0xd2/0x150 really_probe+0xee/0x280 driver_probe_device+0x50/0xc0 bus_for_each_drv+0x84/0xd0 __device_attach+0xe4/0x150 pci_bus_add_device+0x4e/0x70 pci_bus_add_devices+0x2e/0x66 pci_bus_add_devices+0x59/0x66 pci_bus_add_devices+0x59/0x66 enable_slot+0x344/0x450 acpiphp_check_bridge.part.0+0x119/0x150 acpiphp_hotplug_notify+0xaa/0x140 acpi_device_hotplug+0xa2/0x3f0 acpi_hotplug_work_fn+0x1a/0x30 process_one_work+0x234/0x580 worker_thread+0x50/0x3b0 kthread+0x10a/0x140 ret_from_fork+0x3a/0x50 -> #0 (pci_rescan_remove_lock){+.+.}: __lock_acquire+0xe54/0x1ac0 lock_acquire+0xb8/0x1b0 __mutex_lock+0xac/0x9a0 authorized_store+0xe8/0x210 kernfs_fop_write+0x125/0x1b0 vfs_write+0xc2/0x1d0 ksys_write+0x6c/0xf0 do_syscall_64+0x50/0x180 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&tb->lock); lock(pci_rescan_remove_lock); lock(&tb->lock); lock(pci_rescan_remove_lock); *** DEADLOCK *** 5 locks held by pool-/usr/lib/b/1258: #0: 000000003df1a1ad (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x4d/0x60 #1: 0000000095a40b02 (sb_writers#6){.+.+}, at: vfs_write+0x185/0x1d0 #2: 0000000017a7d714 (&of->mutex){+.+.}, at: kernfs_fop_write+0xf2/0x1b0 #3: 000000004f262981 (kn->count#208){.+.+}, at: kernfs_fop_write+0xfa/0x1b0 #4: 00000000bfb796b5 (&tb->lock){+.+.}, at: authorized_store+0x7c/0x210 stack backtrace: CPU: 0 PID: 1258 Comm: pool-/usr/lib/b Tainted: G T 5.3.0-rc6+ #1 On an system using ACPI hotplug the host router gets hotplugged first and then the firmware starts sending notifications about connected devices so the above scenario should not happen in reality. However, after taking a second look at commit a03e828915c0 ("thunderbolt: Serialize PCIe tunnel creation with PCI rescan") that introduced the locking, I don't think it is actually correct. It may have cured the symptom but probably the real root cause was somewhere closer to PCI stack and possibly is already fixed with recent kernels. I also tried to reproduce the original issue with the commit reverted but could not. So to keep lockdep happy and the code bit less complex drop calls to pci_lock_rescan_remove()/pci_unlock_rescan_remove() in tb_switch_set_authorized() effectively reverting a03e828915c0. Link: https://lkml.org/lkml/2019/8/30/513 Fixes: a03e828915c0 ("thunderbolt: Serialize PCIe tunnel creation with PCI rescan") Reported-by: Dominik Brodowski Signed-off-by: Mika Westerberg --- drivers/thunderbolt/switch.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'drivers') diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index 8e712fbf8233..5ea8db667e83 100644 --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -1034,13 +1034,6 @@ static int tb_switch_set_authorized(struct tb_switch *sw, unsigned int val) if (sw->authorized) goto unlock; - /* - * Make sure there is no PCIe rescan ongoing when a new PCIe - * tunnel is created. Otherwise the PCIe rescan code might find - * the new tunnel too early. - */ - pci_lock_rescan_remove(); - switch (val) { /* Approve switch */ case 1: @@ -1060,8 +1053,6 @@ static int tb_switch_set_authorized(struct tb_switch *sw, unsigned int val) break; } - pci_unlock_rescan_remove(); - if (!ret) { sw->authorized = val; /* Notify status change to the userspace */ -- cgit v1.2.3 From 747125db6dcd8bcc21f13d013f6e6a2acade21ee Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Mon, 16 Sep 2019 17:03:03 +0300 Subject: thunderbolt: Drop unnecessary read when writing LC command in Ice Lake The read is not needed as we overwrite the returned value in the next line anyway so drop it. Fixes: 3cdb9446a117 ("thunderbolt: Add support for Intel Ice Lake") Reported-by: Nicholas Johnson Signed-off-by: Mika Westerberg --- drivers/thunderbolt/nhi_ops.c | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers') diff --git a/drivers/thunderbolt/nhi_ops.c b/drivers/thunderbolt/nhi_ops.c index 61cd09cef943..6795851aac95 100644 --- a/drivers/thunderbolt/nhi_ops.c +++ b/drivers/thunderbolt/nhi_ops.c @@ -80,7 +80,6 @@ static void icl_nhi_lc_mailbox_cmd(struct tb_nhi *nhi, enum icl_lc_mailbox_cmd c { u32 data; - pci_read_config_dword(nhi->pdev, VS_CAP_19, &data); data = (cmd << VS_CAP_19_CMD_SHIFT) & VS_CAP_19_CMD_MASK; pci_write_config_dword(nhi->pdev, VS_CAP_19, data | VS_CAP_19_VALID); } -- cgit v1.2.3