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drm/panel: waveshare: Add automatic panel recognition for DSI panels - #3
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EngineerWill merged 2 commits intoAug 13, 2026
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Add support for Waveshare automatic recognition DSI panels which identify themselves at runtime via I2C registers. The driver reads screen type, rotation and refresh rate from registers 0xd0-0xd3 to select the appropriate display mode and DSI lane configuration. Supported configurations include 1200x1920 and 1920x1200 panels at both 30fps (2 lanes) and 60fps (4 lanes) refresh rates. Signed-off-by: Engineer_Will <646689853@qq.com>
Add the auto_rec overlay parameter to select the automatic recognition panel compatible string (waveshare,automatic-recognition-panel). This enables runtime panel detection via I2C for Waveshare DSI displays that support automatic identification. Use lowercase with underscores for the parameter name to follow kernel naming conventions. Signed-off-by: Engineer_Will <646689853@qq.com>
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[ Upstream commit d85f0f0 ] A write command whose data is sent entirely as immediate data is not registered. iser_reg_mem_fastreg() takes the DMA key path and leaves rdma_reg[ISER_DIR_OUT].desc at NULL, while iser_dma_map_task_data() has already set dir[ISER_DIR_OUT]. iser_check_remote_inv() looks at dir[] alone and hands the descriptor to iser_inv_desc(), which reads desc->sig_protected. A target that answers such a command with IB_WR_SEND_WITH_INV faults the initiator. Leaving those commands unregistered is deliberate. The same function already terminates the connection when a target sends a remote invalidation the initiator did not ask for. A target that invalidates a direction that was never registered is in the same class, so give it the same answer. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] CPU: 0 UID: 0 PID: 40 Comm: kworker/u8:2 Not tainted 7.2.0-rc5-ISERHOST-gf5098b6bae76-dirty #3 PREEMPT(lazy) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: rxe_wq do_work RIP: 0010:iser_task_rsp+0x6d6/0xec0 Code: 48 c1 ea 03 80 3c 02 00 0f 85 ba 06 00 00 48 8b 9b 78 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 20 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 76 06 00 00 80 7b 20 00 0f 84 3d 04 RSP: 0018:ffff88811b008db8 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000001848 RDX: 0000000000000004 RSI: 1ffff11021587b12 RDI: 0000000000000020 RBP: ffff88810adc1ae4 R08: ffff888109b7f860 R09: ffffffff90a922c0 R10: ffff88810adc1a1c R11: 000000000000003c R12: ffff888109b7f800 R13: ffff88810adc1acc R14: ffff888109b7f820 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88818a676000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000005afe2b CR3: 000000010af23005 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <IRQ> __ib_process_cq+0xe1/0x390 ib_poll_handler+0x6e/0x200 irq_poll_softirq+0x1df/0x480 ? clockevents_program_event+0x2ba/0x860 ? __pfx_irq_poll_softirq+0x10/0x10 handle_softirqs+0x18e/0x590 ? __pfx_handle_softirqs+0x10/0x10 ? __hrtimer_rearm_deferred+0x156/0x450 do_softirq+0x3b/0x60 </IRQ> <TASK> __local_bh_enable_ip+0x61/0x70 __alloc_skb+0x732/0x890 ? _raw_spin_lock_irqsave+0x85/0xe0 ? __pfx___alloc_skb+0x10/0x10 ? _raw_read_unlock_irqrestore+0x16/0x50 rxe_init_packet+0x16b/0x4f0 prepare_ack_packet+0xb8/0x830 rxe_receiver+0x499/0x9980 ? __pfx_rxe_receiver+0x10/0x10 ? rxe_completer+0x29e5/0x38c0 ? hrtimer_start_range_ns_common+0x75f/0x1730 ? hrtimer_start_range_ns+0xa6/0x2c0 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 ? __pfx_rxe_receiver+0x10/0x10 do_work+0x144/0x470 process_one_work+0x633/0x1030 ? assign_work+0x11d/0x370 worker_thread+0x45b/0xd10 ? __pfx_worker_thread+0x10/0x10 kthread+0x2c6/0x3b0 ? recalc_sigpending+0x15c/0x1e0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x36e/0x5a0 ? __pfx_ret_from_fork+0x10/0x10 ? __switch_to+0x572/0xdd0 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- Fixes: 59caaed ("IB/iser: Support the remote invalidation exception") Signed-off-by: Yehyeong Lee <yhlee@isslab.korea.ac.kr> Link: https://patch.msgid.link/20260819010804.641772-1-yhlee@isslab.korea.ac.kr Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com> Signed-off-by: Leon Romanovsky <leon@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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Add automatic panel recognition support for Waveshare DSI displays,targeting panels such as the 10.1inch DSI LCD (E) that identify themselves at runtime via I2C control registers.
Driver changes (drivers/gpu/drm/panel/panel-waveshare-dsi.c)
ws_panel_i2c_read()helper andws_panel_auto_detect()function which read screen type, rotation and refresh rate from registers 0xd0/0xd1/0xd3.waveshare,automatic-recognition-panelcompatible entry.Overlay changes (vc4-kms-dsi-waveshare-panel)
auto_recoverlay parameter selecting the automatic recognition panel, documented in the overlays README.