Re: [PATCH] usb: xhci-mtk: set the dma max_seg_size
From: Robin Murphy
Date: Thu Jun 29 2023 - 14:11:48 EST
On 2023-06-28 22:00, Ricardo Ribalda wrote:
Allow devices to have dma operations beyond 64K, and avoid warnings such
as:
Hang on, is this actually correct? I just had a vague memory of XHCI
having some restrictions, and sure enough according to the spec it
*does* require buffers to be split at 64KB boundaries, since that's the
maximum length a single TRB can encode - that's exactly the kind of
constraint that the max_seg_size abstraction is intended to represent,
so it seems a bit odd to be explicitly claiming a very different value.
Thanks,
Robin.
DMA-API: xhci-mtk 11200000.usb: mapping sg segment longer than device claims to support [len=98304] [max=65536]
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
Fix warnings such as:
[ 451.089443] ------------[ cut here ]------------
[ 451.089498] DMA-API: xhci-mtk 11200000.usb: mapping sg segment longer than device claims to support [len=98304] [max=65536]
[ 451.089617] WARNING: CPU: 7 PID: 14227 at kernel/dma/debug.c:1163 debug_dma_map_sg+0x5bc/0x950
[ 451.089674] Modules linked in: xfrm_interface tun hci_vhci bridge stp llc veth xt_cgroup xt_MASQUERADE uinput rfcomm ip6table_nat fuse 8021q algif_hash algif_skcipher af_alg r8153_ecm cdc_ether usbnet r8152 mii mtk_vcodec_dec_hw mt7921s mt76_sdio mt7921_common mt76_connac_lib mt76 uvcvideo videobuf2_vmalloc mtk_vcodec_dec v4l2_h264 mtk_vcodec_enc mtk_jpeg v4l2_vp9 videobuf2_dma_contig videobuf2_memops v4l2_mem2mem videobuf2_v4l2 btmtksdio videobuf2_common mtk_vcodec_common btmtk mac80211 snd_sof_mt8186 snd_sof_xtensa_dsp snd_sof_of snd_sof snd_sof_utils mtk_scp mtk_rpmsg rpmsg_core mtk_scp_ipi hid_rmi rmi_core serio bluetooth ecdh_generic ecc cfg80211 lzo_rle lzo_compress zram joydev
[ 451.090285] CPU: 7 PID: 14227 Comm: syz-executor.0 Not tainted 5.15.118-lockdep-19753-g1b0a8b16661d #1 cd3ddfc5e13dbbbea438d3161fcad4d98ec474f4
[ 451.090333] Hardware name: Google Rusty sku196608/196609/196610/196611 board (DT)
[ 451.090356] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 451.090401] pc : debug_dma_map_sg+0x5bc/0x950
[ 451.090433] lr : debug_dma_map_sg+0x5bc/0x950
[ 451.090462] sp : ffffffc01fdd75e0
[ 451.090479] x29: ffffffc01fdd7640 x28: ffffff80c1280300 x27: 0000000000010000
[ 451.090531] x26: ffffff80c1ec9600 x25: 1ffffff01a749501 x24: ffffff80d3a4a800
[ 451.090581] x23: dfffffc000000000 x22: ffffff80d3a4a80c x21: ffffffc00aae5740
[ 451.090631] x20: ffffffffffffffff x19: ffffff80d3a4a810 x18: 0000000000000000
[ 451.090680] x17: 64206e6168742072 x16: 65676e6f6c20746e x15: 656d676573206773
[ 451.090731] x14: 20676e697070616d x13: 0000000000000001 x12: 0000000000000001
[ 451.090779] x11: 0000000000000000 x10: 0000000000040000 x9 : 3c6fd66e79e32400
[ 451.090828] x8 : 3c6fd66e79e32400 x7 : 0000000000000001 x6 : 0000000000000001
[ 451.090877] x5 : ffffffc01fdd7158 x4 : ffffffc00b64e2a0 x3 : ffffffc008f92adc
[ 451.090926] x2 : 0000000100000000 x1 : ffffff8057afd940 x0 : 000000000000006f
[ 451.090976] Call trace:
[ 451.090994] debug_dma_map_sg+0x5bc/0x950
[ 451.091026] dma_alloc_noncontiguous+0x2f4/0x404
[ 451.091060] uvc_alloc_urb_buffers+0x1e8/0x600 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.091150] uvc_video_start_transfer+0xaf4/0x1628 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.091228] uvc_video_start_streaming+0x154/0x2d8 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.091305] uvc_start_streaming+0x20c/0x3d4 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.091379] vb2_start_streaming+0x118/0x400 [videobuf2_common 252dc8c49960dcb8e329e2787100c89e1899c17f]
[ 451.091446] vb2_core_streamon+0x258/0x360 [videobuf2_common 252dc8c49960dcb8e329e2787100c89e1899c17f]
[ 451.091507] vb2_streamon+0x88/0xbc [videobuf2_v4l2 f4acca89bfe3410cd8f3ca536255fc3877fe63db]
[ 451.091555] uvc_queue_streamon+0x44/0x68 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.091631] uvc_ioctl_streamon+0xd8/0x124 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.091705] v4l_streamon+0x74/0xa8
[ 451.091738] __video_do_ioctl+0x90c/0xa40
[ 451.091769] video_usercopy+0xa44/0x1ef8
[ 451.091799] video_ioctl2+0x44/0x58
[ 451.091830] v4l2_ioctl+0x138/0x164
[ 451.091860] __arm64_sys_ioctl+0x154/0x1d0
[ 451.091892] invoke_syscall+0x98/0x278
[ 451.091923] el0_svc_common+0x214/0x274
[ 451.091953] do_el0_svc+0x9c/0x19c
[ 451.091982] el0_svc+0x5c/0xc0
[ 451.092013] el0t_64_sync_handler+0x78/0x108
[ 451.092045] el0t_64_sync+0x1a4/0x1a8
[ 451.092081] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 451.092103] CPU: 7 PID: 14227 Comm: syz-executor.0 Not tainted 5.15.118-lockdep-19753-g1b0a8b16661d #1 cd3ddfc5e13dbbbea438d3161fcad4d98ec474f4
[ 451.092148] Hardware name: Google Rusty sku196608/196609/196610/196611 board (DT)
[ 451.092171] Call trace:
[ 451.092186] dump_backtrace+0x0/0x4e8
[ 451.092219] show_stack+0x34/0x44
[ 451.092247] dump_stack_lvl+0xdc/0x11c
[ 451.092278] dump_stack+0x1c/0x48
[ 451.092307] panic+0x2a4/0x7b8
[ 451.092335] check_panic_on_warn+0xb8/0x104
[ 451.092369] __warn+0x16c/0x230
[ 451.092399] report_bug+0x160/0x280
[ 451.092432] bug_handler+0x48/0xb8
[ 451.092466] call_break_hook+0x180/0x1b4
[ 451.092498] brk_handler+0x30/0xbc
[ 451.092529] do_debug_exception+0x16c/0x31c
[ 451.092563] el1_dbg+0x64/0x80
[ 451.092592] el1h_64_sync_handler+0x70/0xb4
[ 451.092624] el1h_64_sync+0x7c/0x80
[ 451.092653] debug_dma_map_sg+0x5bc/0x950
[ 451.092685] dma_alloc_noncontiguous+0x2f4/0x404
[ 451.092717] uvc_alloc_urb_buffers+0x1e8/0x600 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.092794] uvc_video_start_transfer+0xaf4/0x1628 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.092868] uvc_video_start_streaming+0x154/0x2d8 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.092942] uvc_start_streaming+0x20c/0x3d4 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.093015] vb2_start_streaming+0x118/0x400 [videobuf2_common 252dc8c49960dcb8e329e2787100c89e1899c17f]
[ 451.093079] vb2_core_streamon+0x258/0x360 [videobuf2_common 252dc8c49960dcb8e329e2787100c89e1899c17f]
[ 451.093139] vb2_streamon+0x88/0xbc [videobuf2_v4l2 f4acca89bfe3410cd8f3ca536255fc3877fe63db]
[ 451.093187] uvc_queue_streamon+0x44/0x68 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.093261] uvc_ioctl_streamon+0xd8/0x124 [uvcvideo 1a151fdc876854366480a9c6b7aaa4b7999fb493]
[ 451.093334] v4l_streamon+0x74/0xa8
[ 451.093366] __video_do_ioctl+0x90c/0xa40
[ 451.093398] video_usercopy+0xa44/0x1ef8
[ 451.093428] video_ioctl2+0x44/0x58
[ 451.093457] v4l2_ioctl+0x138/0x164
[ 451.093487] __arm64_sys_ioctl+0x154/0x1d0
[ 451.093518] invoke_syscall+0x98/0x278
[ 451.093548] el0_svc_common+0x214/0x274
[ 451.093578] do_el0_svc+0x9c/0x19c
[ 451.093607] el0_svc+0x5c/0xc0
[ 451.093637] el0t_64_sync_handler+0x78/0x108
[ 451.093669] el0t_64_sync+0x1a4/0x1a8
[ 451.093701] SMP: stopping secondary CPUs
[ 451.093777] Kernel Offset: disabled
[ 451.093797] CPU features: 0xc00181c1,a3300e42
[ 451.093822] Memory Limit: none
Signed-off-by: Ricardo Ribalda Delgado <ribalda@xxxxxxxxxxxx>
---
drivers/usb/host/xhci-mtk.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index 90cf40d6d0c3..605b1e1a5098 100644
--- a/drivers/usb/host/xhci-mtk.c
+++ b/drivers/usb/host/xhci-mtk.c
@@ -643,6 +643,8 @@ static int xhci_mtk_probe(struct platform_device *pdev)
pm_runtime_put_autosuspend(dev);
pm_runtime_forbid(dev);
+ dma_set_max_seg_size(dev, UINT_MAX);
+
return 0;
dealloc_usb3_hcd:
---
base-commit: 1b2c92a1cb2469d8c0079dbf496ab86e22e1cb7c
change-id: 20230628-mtk-usb-bf0059f64bd7
Best regards,