Joe Perches <joe@xxxxxxxxxxx> 於 2019年7月31日週三 下午2:06寫道： > > On Wed, 2019-07-31 at 10:45 +0800, Fuqian Huang wrote: > > 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 > [] > > diff --git 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); > > This makes all 4000+ drm_dbg/DRM_DEBUG uses emit > a trace_printk. > > I suggest instead you make only the interrupt uses > use a different function and not drm_dbg. > > Or maybe add an in_interrupt() check like > > if (in_interrupt()) > printk(KERN_DEBUG etc...) > else > trace_printk(etc...) I will send a v2 patch to fix this. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
