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 in IRQ context. Link: https://lwn.net/Articles/365835 Reviewed-by: Joe Perches <joe@xxxxxxxxxxx> Signed-off-by: Fuqian Huang <huangfq.daxian@xxxxxxxxx> --- Changes in v2: - Only make the interrupt uses the trace_printk to avoid all 4000+ drm_dbg/DRM_DEBUG uses emitting a trace_printk. drivers/gpu/drm/drm_print.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index a17c8a14dba4..747835d16fa6 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -236,9 +236,13 @@ void drm_dbg(unsigned int category, const char *format, ...) vaf.fmt = format; vaf.va = &args; - printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", - __builtin_return_address(0), &vaf); - + if (in_interrupt()) { + trace_printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", + __builtin_return_address(0), &vaf); + } else { + printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", + __builtin_return_address(0), &vaf); + } va_end(args); } EXPORT_SYMBOL(drm_dbg); -- 2.11.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
