linux-kernel - [PATCH v11 11/19] drm_print: wrap drm_dev_dbg in _dynamic_func_call_no

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Date:   Thu,  6 Jan 2022 22:29:34 -0700
From:   Jim Cromie <jim.cromie@...il.com>
To:     jbaron@...mai.com, gregkh@...uxfoundation.org,
        linux@...musvillemoes.dk, rostedt@...dmis.org,
        mathieu.desnoyers@...icios.com, daniel.vetter@...ll.ch,
        seanpaul@...omium.org, robdclark@...il.com,
        dri-devel@...ts.freedesktop.org, amd-gfx@...ts.freedesktop.org,
        intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc:     quic_saipraka@...cinc.com, will@...nel.org,
        catalin.marinas@....com, quic_psodagud@...cinc.com, maz@...nel.org,
        arnd@...db.de, linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, mingo@...hat.com,
        jim.cromie@...il.com
Subject: [PATCH v11 11/19] drm_print: wrap drm_dev_dbg in _dynamic_func_call_no_desc

make drm_dev_dbg() macro CONFIG_DRM_USE_DYNAMIC_DEBUG dependent:

 =N  direct forwarding: drm_dev_dbg -> __drm_dev_dbg()
 =Y  wrap __drm_dev_dbg in _dynamic_func_call_no_desc().

This adds the metadata which creates a /proc/dynamic_debug/control
entry for each callsite, and exposes it for selective enablement.

NB: include header in header so wrapper is available

proof of function:

bash-5.1# grep 'ring test' /proc/dynamic_debug/control
drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c:453 [amdgpu]amdgpu_ring_test_helper =xf "ring test on %s succeeded\012"

less
    452         else
    453                 DRM_DEV_DEBUG(adev->dev, "ring test on %s succeeded\n",
    454                               ring->name);
drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c lines 417-454/458 byte 12536/12575 100%  (press RETURN)

new prdbg callsite counts:
bash-5.1# drms_load
[   20.533990] dyndbg:   1 debug prints in module drm
[   20.535637] ACPI: bus type drm_connector registered
[   20.624951] dyndbg:   2 debug prints in module ttm
[   20.627853] dyndbg:   8 debug prints in module video
[   20.922442] dyndbg: 127 debug prints in module i915
[   20.984159] AMD-Vi: AMD IOMMUv2 functionality not available on this system - This is not a bug.
[   21.310216] dyndbg: 2196 debug prints in module amdgpu
[   21.324537] [drm] amdgpu kernel modesetting enabled.
[   21.325092] amdgpu: CRAT table not found
[   21.325512] amdgpu: Virtual CRAT table created for CPU
[   21.326009] amdgpu: Topology: Add CPU node
[   21.401137] dyndbg:   3 debug prints in module wmi
[   21.532540] dyndbg:   3 debug prints in module nouveau

Signed-off-by: Jim Cromie <jim.cromie@...il.com>
---
 include/drm/drm_print.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index f8fa5af11310..1eef315a0a65 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -383,8 +383,14 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 	}								\
 })

+#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
 #define drm_dev_dbg(dev, eCat, fmt, ...)				\
 	__drm_dev_dbg(dev, eCat, fmt, ##__VA_ARGS__)
+#else
+#define drm_dev_dbg(dev, eCat, fmt, ...)				\
+	_dynamic_func_call_no_desc(fmt, __drm_dev_dbg,			\
+				   dev, eCat, fmt, ##__VA_ARGS__)
+#endif

 /**
  * DRM_DEV_DEBUG() - Debug output for generic drm code
-- 
2.33.1