6.6-stable review patch. If anyone has any objections, please let me know.
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From: Marijn Suijten marijn.suijten@somainline.org
[ Upstream commit 660c396c98c061f9696bebacc178b74072e80054 ]
Ordering issues here cause an uninitialized (default STANDALONE) usecase to be programmed (which appears to be a MUX) in some cases when msm_dsi_host_register() is called, leading to the slave PLL in bonded-DSI mode to source from a clock parent (dsi1vco) that is off.
This should seemingly not be a problem as the actual dispcc clocks from DSI1 that are muxed in the clock tree of DSI0 are way further down, this bit still seems to have an effect on them somehow and causes the right side of the panel controlled by DSI1 to not function.
In an ideal world this code is refactored to no longer have such error-prone calls "across subsystems", and instead model the "PLL src" register field as a regular mux so that changing the clock parents programmatically or in DTS via `assigned-clock-parents` has the desired effect. But for the avid reader, the clocks that we *are* muxing into DSI0's tree are way further down, so if this bit turns out to be a simple mux between dsiXvco and out_div, that shouldn't have any effect as this whole tree is off anyway.
Fixes: 57bf43389337 ("drm/msm/dsi: Pass down use case to PHY") Reviewed-by: Abhinav Kumar quic_abhinavk@quicinc.com Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Patchwork: https://patchwork.freedesktop.org/patch/637650/ Link: https://lore.kernel.org/r/20250217-drm-msm-initial-dualpipe-dsc-fixes-v3-2-9... Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/msm/dsi/dsi_manager.c | 32 ++++++++++++++++++--------- 1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c index 28b8012a21f2b..1a75f9c18c24b 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c @@ -74,17 +74,35 @@ static int dsi_mgr_setup_components(int id) int ret;
if (!IS_BONDED_DSI()) { + /* + * Set the usecase before calling msm_dsi_host_register(), which would + * already program the PLL source mux based on a default usecase. + */ + msm_dsi_phy_set_usecase(msm_dsi->phy, MSM_DSI_PHY_STANDALONE); + msm_dsi_host_set_phy_mode(msm_dsi->host, msm_dsi->phy); + ret = msm_dsi_host_register(msm_dsi->host); if (ret) return ret; - - msm_dsi_phy_set_usecase(msm_dsi->phy, MSM_DSI_PHY_STANDALONE); - msm_dsi_host_set_phy_mode(msm_dsi->host, msm_dsi->phy); } else if (other_dsi) { struct msm_dsi *master_link_dsi = IS_MASTER_DSI_LINK(id) ? msm_dsi : other_dsi; struct msm_dsi *slave_link_dsi = IS_MASTER_DSI_LINK(id) ? other_dsi : msm_dsi; + + /* + * PLL0 is to drive both DSI link clocks in bonded DSI mode. + * + * Set the usecase before calling msm_dsi_host_register(), which would + * already program the PLL source mux based on a default usecase. + */ + msm_dsi_phy_set_usecase(clk_master_dsi->phy, + MSM_DSI_PHY_MASTER); + msm_dsi_phy_set_usecase(clk_slave_dsi->phy, + MSM_DSI_PHY_SLAVE); + msm_dsi_host_set_phy_mode(msm_dsi->host, msm_dsi->phy); + msm_dsi_host_set_phy_mode(other_dsi->host, other_dsi->phy); + /* Register slave host first, so that slave DSI device * has a chance to probe, and do not block the master * DSI device's probe. @@ -98,14 +116,6 @@ static int dsi_mgr_setup_components(int id) ret = msm_dsi_host_register(master_link_dsi->host); if (ret) return ret; - - /* PLL0 is to drive both 2 DSI link clocks in bonded DSI mode. */ - msm_dsi_phy_set_usecase(clk_master_dsi->phy, - MSM_DSI_PHY_MASTER); - msm_dsi_phy_set_usecase(clk_slave_dsi->phy, - MSM_DSI_PHY_SLAVE); - msm_dsi_host_set_phy_mode(msm_dsi->host, msm_dsi->phy); - msm_dsi_host_set_phy_mode(other_dsi->host, other_dsi->phy); }
return 0;