Hi Biju, On Fri, Jun 02, 2023 at 07:29:45PM +0000, Biju Das wrote: > > Subject: [PATCH v2] drm: rcar-du: Use dev_err_probe() to record cause of > > KMS init errors > > > > The (large) rcar_du_modeset_init() function can fail for many reasons, > > two of two involving probe deferral. Use dev_err_probe() in those code > > paths to record the cause of the probe deferral, in order to help > > debugging probe issues. > > > > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx> > > --- > > drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.c | 4 ++++ > > drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c | 8 ++++++-- > > 2 files changed, 10 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.c b/drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.c > > index 12a8839fe3be..5b752adb1b02 100644 > > --- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.c > > +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.c > > @@ -701,6 +701,10 @@ static int rcar_du_probe(struct platform_device *pdev) > > /* DRM/KMS objects */ > > ret = rcar_du_modeset_init(rcdu); > > if (ret < 0) { > > + /* > > + * Don't use dev_err_probe(), as it would overwrite the probe > > + * deferral reason recorded in rcar_du_modeset_init(). > > + */ > > if (ret != -EPROBE_DEFER) > > dev_err(&pdev->dev, > > "failed to initialize DRM/KMS (%d)\n", ret); > > diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c > > index adfb36b0e815..a9b01027bf03 100644 > > --- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c > > +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c > > @@ -932,8 +932,10 @@ int rcar_du_modeset_init(struct rcar_du_device *rcdu) > > > > /* Initialize the Color Management Modules. */ > > ret = rcar_du_cmm_init(rcdu); > > - if (ret) > > + if (ret) { > > + dev_err_probe(rcdu->dev, "failed to initialize CMM\n", ret); > > dev_err_probe(rcdu->dev, ret, "failed to initialize CMM\n"); > > similarly for below one. Oops. I wonder how I missed that, is it fails to even compile. Sorry :-( I'll post a v2. > > return ret; > > + } > > > > /* Create the CRTCs. */ > > for (swindex = 0, hwindex = 0; swindex < rcdu->num_crtcs; ++hwindex) { > > @@ -952,8 +954,10 @@ int rcar_du_modeset_init(struct rcar_du_device *rcdu) > > > > /* Initialize the encoders. */ > > ret = rcar_du_encoders_init(rcdu); > > - if (ret < 0) > > + if (ret < 0) { > > + dev_err_probe(rcdu->dev, "failed to initialize encoders\n", ret); > > return ret; > > + } > > > > if (ret == 0) { > > dev_err(rcdu->dev, "error: no encoder could be initialized\n"); -- Regards, Laurent Pinchart