On 1/17/20 10:09 AM, Sean Paul wrote:
On Fri, Dec 13, 2019 at 3:09 PM <mikita.lipski@xxxxxxx> wrote:From: Mikita Lipski <mikita.lipski@xxxxxxx>Hi Mikita, Unfortunately this patch causes a crash on my i915 device when I unplug my MST hub. The panic is below.
Hi Sean,I thought this issue was fixed by Wayne Lin in https://patchwork.freedesktop.org/patch/346736/?series=71388&rev=1 but now I checked it seems it never got pushed. I will resend Wayne's patch once again.
Thanks Mikita
[ 38.514014] BUG: kernel NULL pointer dereference, address: 0000000000000030 [ 38.521801] #PF: supervisor read access in kernel mode [ 38.527556] #PF: error_code(0x0000) - not-present page [ 38.533299] PGD 0 P4D 0 [ 38.536127] Oops: 0000 [#1] PREEMPT SMP PTI [ 38.540798] CPU: 1 PID: 1324 Comm: DrmThread Not tainted 5.5.0-rc6-02273-g9bb4096398e7 #36 [ 38.550040] Hardware name: Google Fizz/Fizz, BIOS Google_Fizz.10139.39.0 01/04/2018 [ 38.558606] RIP: 0010:drm_dp_mst_atomic_check_bw_limit+0x11/0x102 [ 38.565418] Code: 05 ff cb bf 19 48 f7 f6 c3 0f 1f 44 00 00 55 b8 0b 80 ff 0f 48 89 e5 5d c3 55 48 89 e5 41 57 41 56 41 55 41 54 4c 8d 77 30 53 <48> 8b 47 30 49 89 fd 49 89 f7 45 31 e4 48 8d 58 e8 48 8d 53 18 4c [ 38.586422] RSP: 0018:ffffc9000139f9d8 EFLAGS: 00010282 [ 38.592264] RAX: 0000000000000000 RBX: ffff888272aeac88 RCX: ffff888236f529e0 [ 38.600242] RDX: ffff888272aeac88 RSI: ffff888236f529e0 RDI: 0000000000000000 [ 38.608220] RBP: ffffc9000139fa00 R08: 0000000000000031 R09: 000000000000000e [ 38.616198] R10: ffff888236f529e8 R11: ffff8882621f3440 R12: 0000000000000000 [ 38.624176] R13: ffff888236f529d0 R14: 0000000000000030 R15: ffff888236f529e0 [ 38.632153] FS: 00007cd9229ce700(0000) GS:ffff888276c80000(0000) knlGS:0000000000000000 [ 38.641193] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 38.647616] CR2: 0000000000000030 CR3: 00000002618e8004 CR4: 00000000003606e0 [ 38.655593] Call Trace: [ 38.658329] drm_dp_mst_atomic_check+0x152/0x16d [ 38.663484] intel_atomic_check+0xcfe/0x1e6f [ 38.668259] ? trace_hardirqs_on+0x28/0x3d [ 38.672835] ? intel_pipe_config_compare+0x1b38/0x1b38 [ 38.678580] drm_atomic_check_only+0x5ab/0x70f [ 38.683547] ? drm_atomic_set_crtc_for_connector+0xf5/0x102 [ 38.689778] ? drm_atomic_helper_shutdown+0xb6/0xb6 [ 38.695221] drm_atomic_commit+0x18/0x53 [ 38.699604] drm_atomic_helper_set_config+0x5a/0x70 [ 38.705057] drm_mode_setcrtc+0x2ab/0x833 [ 38.709537] ? rcu_read_unlock+0x57/0x57 [ 38.713920] ? drm_mode_getcrtc+0x173/0x173 [ 38.718594] drm_ioctl+0x2e5/0x424 [ 38.722392] ? drm_mode_getcrtc+0x173/0x173 [ 38.727069] vfs_ioctl+0x21/0x2f [ 38.730675] do_vfs_ioctl+0x5fb/0x61e [ 38.734766] ksys_ioctl+0x55/0x75 [ 38.738469] __x64_sys_ioctl+0x1a/0x1e [ 38.742659] do_syscall_64+0x5c/0x6d [ 38.746653] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.752298] RIP: 0033:0x7cd92552d497 [ 38.756291] Code: 8a 66 90 48 8b 05 d1 d9 2b 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d9 2b 00 f7 d8 64 89 01 48 [ 38.777296] RSP: 002b:00007cd9229cd698 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 38.785762] RAX: ffffffffffffffda RBX: 000020323373da80 RCX: 00007cd92552d497 [ 38.793740] RDX: 00007cd9229cd6d0 RSI: 00000000c06864a2 RDI: 000000000000001c [ 38.801717] RBP: 00007cd9229cd6c0 R08: 0000000000000000 R09: 0000000000000000 [ 38.809693] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000001c [ 38.817670] R13: 0000000000000000 R14: 00007cd9229cd6d0 R15: 00000000c06864a2 [ 38.825642] Modules linked in: xt_nat cdc_ether r8152 bridge stp llc usbhid btusb btrtl btbcm btintel bluetooth asix usbnet ecdh_generic ecc mii snd_soc_hdac_hdmi snd_soc_dmic xhci_pci xhci_hcd snd_soc_skl snd_soc_sst_ipc snd_soc_sst_dsp snd_hda_ext_core snd_intel_dspcfg snd_hda_core usbcore usb_common acpi_als kfifo_buf industrialio xt_MASQUERADE iptable_nat nf_nat xt_mark fuse ip6table_filter iwlmvm mac80211 r8169 realtek iwlwifi lzo_rle lzo_compress zram cfg80211 [ 38.871839] CR2: 0000000000000030 [ 38.875542] ---[ end trace 6bb39ec52e30c7cb ]--- [ 38.886142] RIP: 0010:drm_dp_mst_atomic_check_bw_limit+0x11/0x102 [ 38.892957] Code: 05 ff cb bf 19 48 f7 f6 c3 0f 1f 44 00 00 55 b8 0b 80 ff 0f 48 89 e5 5d c3 55 48 89 e5 41 57 41 56 41 55 41 54 4c 8d 77 30 53 <48> 8b 47 30 49 89 fd 49 89 f7 45 31 e4 48 8d 58 e8 48 8d 53 18 4c [ 38.913964] RSP: 0018:ffffc9000139f9d8 EFLAGS: 00010282 [ 38.919804] RAX: 0000000000000000 RBX: ffff888272aeac88 RCX: ffff888236f529e0 [ 38.927784] RDX: ffff888272aeac88 RSI: ffff888236f529e0 RDI: 0000000000000000 [ 38.935765] RBP: ffffc9000139fa00 R08: 0000000000000031 R09: 000000000000000e [ 38.943733] R10: ffff888236f529e8 R11: ffff8882621f3440 R12: 0000000000000000 [ 38.951712] R13: ffff888236f529d0 R14: 0000000000000030 R15: ffff888236f529e0 [ 38.959692] FS: 00007cd9229ce700(0000) GS:ffff888276c80000(0000) knlGS:0000000000000000 [ 38.968730] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 38.975144] CR2: 0000000000000030 CR3: 00000002618e8004 CR4: 00000000003606e0 [ 38.983121] Kernel panic - not syncing: Fatal exception [ 38.988967] Kernel Offset: disabled [ 38.998280] ---[ end Kernel panic - not syncing: Fatal exception ]---[why] Adding PBN attribute to drm_dp_vcpi_allocation structure to keep track of how much bandwidth each Port requires. Adding drm_dp_mst_atomic_check_bw_limit to verify that state's bandwidth needs doesn't exceed available bandwidth. The funtion is called in drm_dp_mst_atomic_check after drm_dp_mst_atomic_check_topology_state to fully verify that the proposed topology is supported. v2: Fixing some typos and indentations Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx> Signed-off-by: Mikita Lipski <mikita.lipski@xxxxxxx> --- drivers/gpu/drm/drm_dp_mst_topology.c | 66 ++++++++++++++++++++++++++- include/drm/drm_dp_mst_helper.h | 1 + 2 files changed, 65 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 7cd505e771ff..f8b72ac79c66 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -4052,7 +4052,7 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state, { struct drm_dp_mst_topology_state *topology_state; struct drm_dp_vcpi_allocation *pos, *vcpi = NULL; - int prev_slots, req_slots; + int prev_slots, prev_bw, req_slots; topology_state = drm_atomic_get_mst_topology_state(state, mgr); if (IS_ERR(topology_state)) @@ -4063,6 +4063,7 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state, if (pos->port == port) { vcpi = pos; prev_slots = vcpi->vcpi; + prev_bw = vcpi->pbn; /* * This should never happen, unless the driver tries @@ -4078,8 +4079,10 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state, break; } } - if (!vcpi) + if (!vcpi) { prev_slots = 0; + prev_bw = 0; + } if (pbn_div <= 0) pbn_div = mgr->pbn_div; @@ -4089,6 +4092,9 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state, DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n", port->connector->base.id, port->connector->name, port, prev_slots, req_slots); + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n", + port->connector->base.id, port->connector->name, + port, prev_bw, pbn); /* Add the new allocation to the state */ if (!vcpi) { @@ -4101,6 +4107,7 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state, list_add(&vcpi->next, &topology_state->vcpis); } vcpi->vcpi = req_slots; + vcpi->pbn = pbn; return req_slots; } @@ -4677,6 +4684,58 @@ static void drm_dp_mst_destroy_state(struct drm_private_obj *obj, kfree(mst_state); } +static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port, + struct drm_dp_mst_branch *branch) +{ + while (port->parent) { + if (port->parent == branch) + return true; + + if (port->parent->port_parent) + port = port->parent->port_parent; + else + break; + } + return false; +} + +static inline +int drm_dp_mst_atomic_check_bw_limit(struct drm_dp_mst_branch *branch, + struct drm_dp_mst_topology_state *mst_state) +{ + struct drm_dp_mst_port *port; + struct drm_dp_vcpi_allocation *vcpi; + int pbn_limit = 0, pbn_used = 0; + + list_for_each_entry(port, &branch->ports, next) { + if (port->mstb) + if (drm_dp_mst_atomic_check_bw_limit(port->mstb, mst_state)) + return -EINVAL; + + if (port->available_pbn > 0) + pbn_limit = port->available_pbn; + } + DRM_DEBUG_ATOMIC("[MST BRANCH:%p] branch has %d PBN available\n", + branch, pbn_limit); + + list_for_each_entry(vcpi, &mst_state->vcpis, next) { + if (!vcpi->pbn) + continue; + + if (drm_dp_mst_port_downstream_of_branch(vcpi->port, branch)) + pbn_used += vcpi->pbn; + } + DRM_DEBUG_ATOMIC("[MST BRANCH:%p] branch used %d PBN\n", + branch, pbn_used); + + if (pbn_used > pbn_limit) { + DRM_DEBUG_ATOMIC("[MST BRANCH:%p] No available bandwidth\n", + branch); + return -EINVAL; + } + return 0; +} + static inline int drm_dp_mst_atomic_check_topology_state(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_topology_state *mst_state) @@ -4808,6 +4867,9 @@ int drm_dp_mst_atomic_check(struct drm_atomic_state *state) ret = drm_dp_mst_atomic_check_topology_state(mgr, mst_state); if (ret) break; + ret = drm_dp_mst_atomic_check_bw_limit(mgr->mst_primary, mst_state); + if (ret) + break; } return ret; diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index 830c94b7f45d..2919d9776af3 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -502,6 +502,7 @@ struct drm_dp_payload { struct drm_dp_vcpi_allocation { struct drm_dp_mst_port *port; int vcpi; + int pbn; bool dsc_enabled; struct list_head next; }; -- 2.17.1 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Fdri-devel&data=02%7C01%7Cmikita.lipski%40amd.com%7C2b736cb4c0f1456691ec08d79b5f4c69%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637148705931074877&sdata=s4q0ni0H%2FiPgonlMMK9Od7UK5M%2FC%2F0rsQEGsr1FP0XU%3D&reserved=0
-- Thanks, Mikita Lipski Software Engineer 2, AMD mikita.lipski@xxxxxxx _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
