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Subject[PATCH] drm: use trace_printk rather than printk in drm_dbg.
Date
In drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c,
amdgpu_ih_process calls DRM_DEBUG which calls drm_dbg and
finally calls printk.
As amdgpu_ih_process is called from an interrupt handler,
and interrupt handler should be short as possible.

As printk may lead to bogging down the system or can even
create a live lock. printk should not be used in IRQ context.
Instead, trace_printk is recommended.
Link: https://lwn.net/Articles/365835

Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
---
drivers/gpu/drm/drm_print.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index a17c8a14dba4..90cded140146 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -236,7 +236,7 @@ void drm_dbg(unsigned int category, const char *format, ...)
vaf.fmt = format;
vaf.va = &args;

- printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
+ trace_printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
__builtin_return_address(0), &vaf);

va_end(args);
--
2.11.0
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