| Message ID | 20211015231307.1784165-1-bjorn.andersson@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | drm/msm/dp: Only create debugfs for PRIMARY minor | expand |
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? 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? > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> > --- > 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);
On Fri 15 Oct 18:44 CDT 2021, abhinavk@codeaurora.org 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@linaro.org> > > --- > > 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);
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);
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. Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> --- drivers/gpu/drm/msm/dp/dp_display.c | 5 +++++ 1 file changed, 5 insertions(+) -- 2.29.2