From: Marek Vasut Date: Sat, 10 Jan 2026 17:14:10 +0000 (+0100) Subject: drm/imx: parallel-display: Prefer bus format set via legacy "interface-pix-fmt" DT... X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=cdf26e1462c220629bb79d487263b66f8b679eab;p=thirdparty%2Fkernel%2Flinux.git drm/imx: parallel-display: Prefer bus format set via legacy "interface-pix-fmt" DT property Prefer bus format set via legacy "interface-pix-fmt" DT property over panel bus format. This is necessary to retain support for DTs which configure the IPUv3 parallel output as 24bit DPI, but connect 18bit DPI panels to it with hardware swizzling. This used to work up to Linux 6.12, but stopped working in 6.13, reinstate the behavior to support old DTs. Cc: stable@vger.kernel.org Fixes: 5f6e56d3319d ("drm/imx: parallel-display: switch to drm_panel_bridge") Signed-off-by: Marek Vasut Reviewed-by: Philipp Zabel Signed-off-by: Philipp Zabel Link: https://patch.msgid.link/20260110171510.692666-1-marex@nabladev.com --- diff --git a/drivers/gpu/drm/imx/ipuv3/parallel-display.c b/drivers/gpu/drm/imx/ipuv3/parallel-display.c index 4ce772bc3cb3a..a356f0b764cb7 100644 --- a/drivers/gpu/drm/imx/ipuv3/parallel-display.c +++ b/drivers/gpu/drm/imx/ipuv3/parallel-display.c @@ -110,8 +110,7 @@ imx_pd_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge, output_fmt = imxpd->bus_format ? : MEDIA_BUS_FMT_RGB888_1X24; /* Now make sure the requested output format is supported. */ - if ((imxpd->bus_format && imxpd->bus_format != output_fmt) || - !imx_pd_format_supported(output_fmt)) { + if (!imx_pd_format_supported(output_fmt)) { *num_input_fmts = 0; return NULL; } @@ -121,7 +120,17 @@ imx_pd_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge, if (!input_fmts) return NULL; - input_fmts[0] = output_fmt; + /* + * Prefer bus format set via legacy "interface-pix-fmt" DT property + * over panel bus format. This is necessary to retain support for + * DTs which configure the IPUv3 parallel output as 24bit, but + * connect 18bit DPI panels to it with hardware swizzling. + */ + if (imxpd->bus_format && imxpd->bus_format != output_fmt) + input_fmts[0] = imxpd->bus_format; + else + input_fmts[0] = output_fmt; + return input_fmts; }