From a97508759c144cbe7f1b25ba0e671672f71087d6 Mon Sep 17 00:00:00 2001 From: jsg Date: Sun, 12 Apr 2026 23:05:35 +0000 Subject: [PATCH] drm/amd/display: Fix NULL pointer dereference in dcn401_init_hw() From Srinivasan Shanmugam 10c13c111d0d7f8e101c742feff264fc98e3f9f7 in linux-6.18.y/6.18.22 e927b36ae18b66b49219eaa9f46edc7b4fdbb25e in mainline linux --- .../amd/display/dc/hwss/dcn401/dcn401_hwseq.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/sys/dev/pci/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c b/sys/dev/pci/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c index ae505f1e919..b89cb03dc68 100644 --- a/sys/dev/pci/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c +++ b/sys/dev/pci/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c @@ -143,6 +143,7 @@ void dcn401_init_hw(struct dc *dc) int edp_num; uint32_t backlight = MAX_BACKLIGHT_LEVEL; uint32_t user_level = MAX_BACKLIGHT_LEVEL; + bool dchub_ref_freq_changed; int current_dchub_ref_freq = 0; if (dc->clk_mgr && dc->clk_mgr->funcs && dc->clk_mgr->funcs->init_clocks) { @@ -357,14 +358,18 @@ void dcn401_init_hw(struct dc *dc) dc->caps.dmub_caps.psr = dc->ctx->dmub_srv->dmub->feature_caps.psr; dc->caps.dmub_caps.mclk_sw = dc->ctx->dmub_srv->dmub->feature_caps.fw_assisted_mclk_switch_ver > 0; dc->caps.dmub_caps.fams_ver = dc->ctx->dmub_srv->dmub->feature_caps.fw_assisted_mclk_switch_ver; + + /* sw and fw FAMS versions must match for support */ dc->debug.fams2_config.bits.enable &= - dc->caps.dmub_caps.fams_ver == dc->debug.fams_version.ver; // sw & fw fams versions must match for support - if ((!dc->debug.fams2_config.bits.enable && dc->res_pool->funcs->update_bw_bounding_box) - || res_pool->ref_clocks.dchub_ref_clock_inKhz / 1000 != current_dchub_ref_freq) { + dc->caps.dmub_caps.fams_ver == dc->debug.fams_version.ver; + dchub_ref_freq_changed = + res_pool->ref_clocks.dchub_ref_clock_inKhz / 1000 != current_dchub_ref_freq; + if ((!dc->debug.fams2_config.bits.enable || dchub_ref_freq_changed) && + dc->res_pool->funcs->update_bw_bounding_box && + dc->clk_mgr && dc->clk_mgr->bw_params) { /* update bounding box if FAMS2 disabled, or if dchub clk has changed */ - if (dc->clk_mgr) - dc->res_pool->funcs->update_bw_bounding_box(dc, - dc->clk_mgr->bw_params); + dc->res_pool->funcs->update_bw_bounding_box(dc, + dc->clk_mgr->bw_params); } } }