> -----Original Message----- > From: dri-devel <[email protected]> On Behalf Of Hugo > Villeneuve > Sent: 12 January 2026 15:43 > Subject: [PATCH] drm: renesas: rz-du: mipi_dsi: fix kernel panic when > rebooting for some panels > > From: Hugo Villeneuve <[email protected]> > > Since commit 56de5e305d4b ("clk: renesas: r9a07g044: Add MSTOP for RZ/G2L") > we may get the following > kernel panic, for some panels, when rebooting: > > systemd-shutdown[1]: Rebooting. > Call trace: > ... > do_serror+0x28/0x68 > el1h_64_error_handler+0x34/0x50 > el1h_64_error+0x6c/0x70 > rzg2l_mipi_dsi_host_transfer+0x114/0x458 (P) > mipi_dsi_device_transfer+0x44/0x58 > mipi_dsi_dcs_set_display_off_multi+0x9c/0xc4 > ili9881c_unprepare+0x38/0x88 > drm_panel_unprepare+0xbc/0x108 > > This happens for panels that need to send MIPI-DSI commands in their > unprepare() callback. Since the MIPI-DSI interface is stopped at that point, > rzg2l_mipi_dsi_host_transfer() triggers the kernel panic. > > Fix by moving rzg2l_mipi_dsi_stop() to new callback function > rzg2l_mipi_dsi_atomic_post_disable(). > > With this change we now have the correct power-down/stop sequence: > > systemd-shutdown[1]: Rebooting. > rzg2l-mipi-dsi 10850000.dsi: rzg2l_mipi_dsi_atomic_disable(): entry > ili9881c-dsi 10850000.dsi.0: ili9881c_unprepare(): entry > rzg2l-mipi-dsi 10850000.dsi: rzg2l_mipi_dsi_atomic_post_disable(): entry > reboot: Restarting system > > Suggested-by: Biju Das <[email protected]> > Signed-off-by: Hugo Villeneuve <[email protected]> > --- > Tested on a custom RZ/G2L board with three different panels/drivers: > ili9881c -> sending DSI commands in unprepare() > jd9365da -> not sending DSI commands in unprepare() > st7703 -> not sending DSI commands in unprepare() > --- > drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c > b/drivers/gpu/drm/renesas/rz- > du/rzg2l_mipi_dsi.c > index 3b52dfc0ea1e0..b164e3a62cc2f 100644 > --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c > +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c > @@ -646,6 +646,13 @@ static void rzg2l_mipi_dsi_atomic_disable(struct > drm_bridge *bridge, > > rzg2l_mipi_dsi_stop_video(dsi); > rzg2l_mipi_dsi_stop_hs_clock(dsi); > +} > + > +static void rzg2l_mipi_dsi_atomic_post_disable(struct drm_bridge *bridge, > + struct drm_atomic_state *state) { > + struct rzg2l_mipi_dsi *dsi = bridge_to_rzg2l_mipi_dsi(bridge); > + > rzg2l_mipi_dsi_stop(dsi); > } > > @@ -681,6 +688,7 @@ static const struct drm_bridge_funcs > rzg2l_mipi_dsi_bridge_ops = { > .atomic_pre_enable = rzg2l_mipi_dsi_atomic_pre_enable, > .atomic_enable = rzg2l_mipi_dsi_atomic_enable, > .atomic_disable = rzg2l_mipi_dsi_atomic_disable, > + .atomic_post_disable = rzg2l_mipi_dsi_atomic_post_disable, > .mode_valid = rzg2l_mipi_dsi_bridge_mode_valid, }; > > > base-commit: 0f61b1860cc3f52aef9036d7235ed1f017632193 > -- > 2.47.3
Queued to drm-misc-next. Cheers, Biju
