From: Brendan Tam Date: Fri, 14 Mar 2025 17:09:13 +0000 (-0400) Subject: drm/amd/display: prevent hang on link training fail X-Git-Tag: v6.12.25~71 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0363c03672cd3191f037905bf981eb523a3b71b1;p=thirdparty%2Fkernel%2Fstable.git drm/amd/display: prevent hang on link training fail commit 8058061ed9d6bc259d1e678607b07d259342c08f upstream. [Why] When link training fails, the phy clock will be disabled. However, in enable_streams, it is assumed that link training succeeded and the mux selects the phy clock, causing a hang when a register write is made. [How] When enable_stream is hit, check if link training failed. If it did, fall back to the ref clock to avoid a hang and keep the system in a recoverable state. Reviewed-by: Dillon Varone Signed-off-by: Brendan Tam Signed-off-by: Aurabindo Pillai Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c index 36d12db8d0225..f5f1ccd8303cf 100644 --- a/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c +++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c @@ -3003,7 +3003,11 @@ void dcn20_enable_stream(struct pipe_ctx *pipe_ctx) dccg->funcs->set_dpstreamclk(dccg, DTBCLK0, tg->inst, dp_hpo_inst); phyd32clk = get_phyd32clk_src(link); - dccg->funcs->enable_symclk32_se(dccg, dp_hpo_inst, phyd32clk); + if (link->cur_link_settings.link_rate == LINK_RATE_UNKNOWN) { + dccg->funcs->disable_symclk32_se(dccg, dp_hpo_inst); + } else { + dccg->funcs->enable_symclk32_se(dccg, dp_hpo_inst, phyd32clk); + } } else { if (dccg->funcs->enable_symclk_se) dccg->funcs->enable_symclk_se(dccg, stream_enc->stream_enc_inst, diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c index 0b743669f23b4..62f1e597787e6 100644 --- a/drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c +++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c @@ -1001,8 +1001,11 @@ void dcn401_enable_stream(struct pipe_ctx *pipe_ctx) if (dc_is_dp_signal(pipe_ctx->stream->signal) || dc_is_virtual_signal(pipe_ctx->stream->signal)) { if (dc->link_srv->dp_is_128b_132b_signal(pipe_ctx)) { dccg->funcs->set_dpstreamclk(dccg, DPREFCLK, tg->inst, dp_hpo_inst); - - dccg->funcs->enable_symclk32_se(dccg, dp_hpo_inst, phyd32clk); + if (link->cur_link_settings.link_rate == LINK_RATE_UNKNOWN) { + dccg->funcs->disable_symclk32_se(dccg, dp_hpo_inst); + } else { + dccg->funcs->enable_symclk32_se(dccg, dp_hpo_inst, phyd32clk); + } } else { /* need to set DTBCLK_P source to DPREFCLK for DP8B10B */ dccg->funcs->set_dtbclk_p_src(dccg, DPREFCLK, tg->inst);