On Fri 15 Oct 18:44 CDT 2021, abhinavk@xxxxxxxxxxxxxx wrote: > On 2021-10-15 16:13, Bjorn Andersson wrote: > > dpu_kms_debugfs_init() and hence dp_debug_get() gets invoked for each > > minor being registered. But dp_debug_get() will allocate a new struct > > dp_debug for each call and this will be associated as dp->debug. > > > > As such dp_debug will create debugfs files in both the PRIMARY and the > > RENDER minor's debugfs directory, but only the last reference will be > > remembered. > > > > The only use of this reference today is in the cleanup path in > > dp_display_deinit_sub_modules() and the dp_debug_private object does > > outlive the debugfs entries in either case, so there doesn't seem to be > > any adverse effects of this, but per the code the current behavior is > > unexpected, so change it to only create dp_debug for the PRIMARY minor. > > > > If i understand correctly, today because of this, we get redundant debugfs > nodes right? > > /sys/kernel/debug/dri/<minor_x>/dp_debug > /sys/kernel/debug/dri/<minor_y>/dp_debug > > Both of these will hold the same information as they are for the same DP > controller right? That's correct, all the dp_debug debugfs files end up in both minors. The problem is that dp->debug points to the dp_debug struct for one of them, which afaict doesn't have any really bad effects today - unless you try to clean up the dp_debug state, but that will clear out the entire dri/<minor_y>... > In that case, this is true even for the other DPU kms information too. > > Why not move this check one level up to dpu_kms_debugfs_init? > I was expecting that perhaps some of this information was minor-specific, but if that isn't the case it sounds reasonable that we should push this one step up. Regards, Bjorn > > Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> > > --- > > drivers/gpu/drm/msm/dp/dp_display.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c > > b/drivers/gpu/drm/msm/dp/dp_display.c > > index 3aa67c53dbc0..06773b58bb60 100644 > > --- a/drivers/gpu/drm/msm/dp/dp_display.c > > +++ b/drivers/gpu/drm/msm/dp/dp_display.c > > @@ -10,6 +10,7 @@ > > #include <linux/component.h> > > #include <linux/of_irq.h> > > #include <linux/delay.h> > > +#include <drm/drm_file.h> > > #include <drm/drm_panel.h> > > > > #include "msm_drv.h" > > @@ -1463,6 +1464,10 @@ void msm_dp_debugfs_init(struct msm_dp > > *dp_display, struct drm_minor *minor) > > dp = container_of(dp_display, struct dp_display_private, dp_display); > > dev = &dp->pdev->dev; > > > > + /* Only create one set of debugfs per DP instance */ > > + if (minor->type != DRM_MINOR_PRIMARY) > > + return; > > + > > dp->debug = dp_debug_get(dev, dp->panel, dp->usbpd, > > dp->link, dp->dp_display.connector, > > minor);
