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Wed, 07 Jan 2026 16:48:40 -0500 Date: Wed, 7 Jan 2026 16:48:39 -0500 From: Hugo Villeneuve To: dri-devel@lists.freedesktop.org Cc: linux-renesas-soc@vger.kernel.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, Claudiu Beznea , Neil Armstrong , Jessica Zhang , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Biju Das Biju Das , Chris Brandt Message-Id: <20260107164839.a490a194d975edc399d72d01@hugovil.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 70.80.174.168 X-SA-Exim-Mail-From: hugo@hugovil.com X-Spam-Level: X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP Subject: [BUG] drm/panel: ilitek-ili9881c: kernel panic on reboot X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.hugovil.com) Hi, when issuing a reboot command, I encounter the following kernel panic: [ 36.183478] SError Interrupt on CPU1, code 0x00000000be000011 -- SError [ 36.183492] CPU: 1 UID: 0 PID: 1 Comm: systemd-shutdow Tainted: G M 6.19.0-rc4-arm64-renesas-00019-g067a81578add #62 NONE [ 36.183504] Tainted: [M]=MACHINE_CHECK [ 36.183507] Hardware name: Gecko ECO2 nxtpad (DT) [ 36.183512] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 36.183519] pc : rzg2l_mipi_dsi_host_transfer+0x114/0x458 [ 36.183538] lr : rzg2l_mipi_dsi_host_transfer+0x98/0x458 [ 36.183547] sp : ffff8000813db860 [ 36.183550] x29: ffff8000813db890 x28: ffff800080c602c0 x27: ffff000009dd7450 [ 36.183563] x26: ffff800080c5fcc0 x25: ffff000009dd7450 x24: ffff800080e1f7a8 [ 36.183573] x23: ffff000009dd7400 x22: 0000000000000000 x21: ffff000009dd7430 [ 36.183582] x20: ffff8000813db8e8 x19: 0000000002050028 x18: 00000000ffffffff [ 36.183592] x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000813db220 [ 36.183602] x14: 0000000000000000 x13: ffff800081255bc0 x12: 00000000000009a2 [ 36.183611] x11: 0000000000000336 x10: ffff8000812b28d0 x9 : ffff800081255bc0 [ 36.183621] x8 : ffff800081399000 x7 : ffff00000a042600 x6 : 0000000000000000 [ 36.183631] x5 : 0000000000000805 x4 : 0000000002000000 x3 : 0000000000000028 [ 36.183640] x2 : 0000000049627000 x1 : ffff800080c60b40 x0 : ffff800081780000 [ 36.183652] Kernel panic - not syncing: Asynchronous SError Interrupt [ 36.183657] CPU: 1 UID: 0 PID: 1 Comm: systemd-shutdow Tainted: G M 6.19.0-rc4-arm64-renesas-00019-g067a81578add #62 NONE [ 36.183665] Tainted: [M]=MACHINE_CHECK [ 36.183668] Hardware name: devboard1 (DT) [ 36.183672] Call trace: [ 36.183675] show_stack+0x18/0x24 (C) [ 36.183692] dump_stack_lvl+0x34/0x8c [ 36.183702] dump_stack+0x18/0x24 [ 36.183708] vpanic+0x314/0x35c [ 36.183716] nmi_panic+0x0/0x64 [ 36.183722] add_taint+0x0/0xbc [ 36.183728] arm64_serror_panic+0x70/0x80 [ 36.183735] do_serror+0x28/0x68 [ 36.183742] el1h_64_error_handler+0x34/0x50 [ 36.183751] el1h_64_error+0x6c/0x70 [ 36.183758] rzg2l_mipi_dsi_host_transfer+0x114/0x458 (P) [ 36.183770] mipi_dsi_device_transfer+0x44/0x58 [ 36.183781] mipi_dsi_dcs_set_display_off_multi+0x9c/0xc4 [ 36.183792] ili9881c_unprepare+0x38/0x88 [ 36.183802] drm_panel_unprepare+0xbc/0x108 [ 36.183814] panel_bridge_atomic_post_disable+0x50/0x60 [ 36.183823] drm_atomic_bridge_call_post_disable+0x24/0x4c [ 36.183835] drm_atomic_bridge_chain_post_disable+0xa8/0x100 [ 36.183845] drm_atomic_helper_commit_modeset_disables+0x2fc/0x5f8 [ 36.183856] drm_atomic_helper_commit_tail_rpm+0x24/0x7c [ 36.183865] commit_tail+0xa4/0x18c [ 36.183874] drm_atomic_helper_commit+0x17c/0x194 [ 36.183884] drm_atomic_commit+0x8c/0xcc [ 36.183892] drm_atomic_helper_disable_all+0x200/0x210 [ 36.183901] drm_atomic_helper_shutdown+0xa8/0x150 [ 36.183911] rzg2l_du_shutdown+0x18/0x24 [ 36.183920] platform_shutdown+0x24/0x34 [ 36.183931] device_shutdown+0x128/0x284 [ 36.183938] kernel_restart+0x44/0xa4 [ 36.183950] __do_sys_reboot+0x178/0x270 [ 36.183959] __arm64_sys_reboot+0x24/0x30 [ 36.183968] invoke_syscall.constprop.0+0x50/0xe4 [ 36.183979] do_el0_svc+0x40/0xc0 [ 36.183988] el0_svc+0x3c/0x164 [ 36.183995] el0t_64_sync_handler+0xa0/0xe4 [ 36.184002] el0t_64_sync+0x198/0x19c [ 36.184020] Kernel Offset: disabled [ 36.184022] CPU features: 0x200000,00020001,4000c501,0400720b [ 36.184028] Memory Limit: none [ 36.495305] ---[ end Kernel panic - not syncing: Asynchronous SError Interrupt ]--- The problem is present since linux-6.18-rc1, but not in linux-6.17. I also confirm the bug is present in linux-6.19-rc4. The bug seems to be happening in rzg2l_mipi_dsi_host_transfer(). After bisecting, here is the first bad commit: commit 56de5e305d4b ("clk: renesas: r9a07g044: Add MSTOP for RZ/G2L") Reverting this change makes the bug disappear. My limited understanding seems to indicate that the MIPI/DSI host may no longer be available/on when the panel tries to send MIPI/DSI commands in ili9881c_unprepare(), maybe because the MIPI/DSI clock has been stopped... The exact same board with two other panels (jd9365da and st7703) doesn't have the bug. -- Hugo Villeneuve