On Fri, Nov 09, 2018 at 11:37:17AM +0530, Rajendra Nayak wrote: > > On 11/2/2018 6:19 PM, Jayant Shekhar wrote: > > In case of msm drm bind failure, dpu_mdss_destroy is triggered. > > In this function, resources are freed and pm runtime disable is > > called, which triggers dpu_mdss_disable. Now in dpu_mdss_disable, > > driver tries to access a memory which is already freed. This > > results in kernel panic. Fix this by ensuring proper sequence > > of dpu destroy and disable calls. > > > > Changes in v2: > > - Removed double spacings [Jeykumar] > > > > Signed-off-by: Jayant Shekhar <jshekhar@xxxxxxxxxxxxxx> > > I was testing this patch out and in my setup I see that with this > change, during a dsi probe defer case, a dpu_mdss_enable() is called > followed by a dpu_mdss_destroy() but dpu_mdss_disable() is never called. > > This results in a mismatch in clock usecount causing the mdp clocks to > stay enabled even with display turned off. This suggests an unmatched pm_runtime_get/put. I just audited the code and nothing stuck out to me in the probe defer case, things seem to be well matched. Could you instrument the pm_runtime_* calls in msm/dpu and see if there's a _get without a _put? Sean > > localhost ~ # cat /sys/kernel/debug/clk/clk_summary | grep mdss > disp_cc_mdss_rscc_ahb_clk 0 0 0 0 0 0 50000 > disp_cc_mdss_axi_clk 0 0 0 0 0 0 50000 > disp_cc_mdss_ahb_clk 0 0 0 0 0 0 50000 > disp_cc_mdss_mdp_clk_src 1 1 0 19200000 0 0 50000 > disp_cc_mdss_mdp_lut_clk 0 0 0 19200000 0 0 50000 > disp_cc_mdss_mdp_clk 1 1 0 19200000 0 0 50000 > disp_cc_mdss_vsync_clk_src 0 0 0 19200000 0 0 50000 > > Also to note, on an older 4.14 kernel, I do not see any issue in the order in which > these functions are called in the dsi probe defer case, i.e its an enable followed by > a disable and then a destroy (and that's without this patch) > > > --- > > drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c | 5 +---- > > 1 file changed, 1 insertion(+), 4 deletions(-) > > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c > > index fd9c893..902bb4c 100644 > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c > > @@ -156,18 +156,15 @@ static void dpu_mdss_destroy(struct drm_device *dev) > > struct dpu_mdss *dpu_mdss = to_dpu_mdss(priv->mdss); > > struct dss_module_power *mp = &dpu_mdss->mp; > > + pm_runtime_disable(dev->dev); > > _dpu_mdss_irq_domain_fini(dpu_mdss); > > - > > free_irq(platform_get_irq(pdev, 0), dpu_mdss); > > - > > msm_dss_put_clk(mp->clk_config, mp->num_clk); > > devm_kfree(&pdev->dev, mp->clk_config); > > if (dpu_mdss->mmio) > > devm_iounmap(&pdev->dev, dpu_mdss->mmio); > > dpu_mdss->mmio = NULL; > > - > > - pm_runtime_disable(dev->dev); > > priv->mdss = NULL; > > } > > > _______________________________________________ > Freedreno mailing list > Freedreno@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/freedreno -- Sean Paul, Software Engineer, Google / Chromium OS
