Hi Arnd,

On Wed, 2016-07-13 at 15:08 +0200, Arnd Bergmann wrote:

On Wednesday, July 13, 2016 5:56:26 PM CEST tiffany lin wrote:

quoted

quoted

diff --git a/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc.c b/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc.c
index 6dcae0a0a1f2..0b25a8700877 100644
--- a/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc.c
+++ b/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc.c

@@ -1028,15 +1028,15 @@ static void mtk_venc_worker(struct work_struct *work)
      bs_buf.size = (size_t)dst_buf->planes[0].length;
 
      mtk_v4l2_debug(2,
-                     "Framebuf VA=%p PA=%llx Size=0x%lx;VA=%p PA=0x%llx Size=0x%lx;VA=%p PA=0x%llx Size=%zu",
+                     "Framebuf VA=%p PA=%pad Size=0x%zx;VA=%p PA=%pad Size=0x%zx;VA=%p PA=%pad Size=0x%zx",
                      frm_buf.fb_addr[0].va,
-                     (u64)frm_buf.fb_addr[0].dma_addr,
+                     &frm_buf.fb_addr[0].dma_addr,
                      frm_buf.fb_addr[0].size,
                      frm_buf.fb_addr[1].va,
-                     (u64)frm_buf.fb_addr[1].dma_addr,
+                     &frm_buf.fb_addr[1].dma_addr,
                      frm_buf.fb_addr[1].size,
                      frm_buf.fb_addr[2].va,
-                     (u64)frm_buf.fb_addr[2].dma_addr,
+                     &frm_buf.fb_addr[2].dma_addr,
                      frm_buf.fb_addr[2].size);

This change will make debug message dump address of dma_addr field but
not the value of the dma_addr we want.
How about change it from
PA=%llx -> PA=%u
(u64)frm_buf.fb_addr[0].dma_addr -> (u32)frm_buf.fb_addr[0].dma_addr,

The %llx works fine with the cast to u64, the change above is mainly for the "%lx"
on a size_t causing a warning.

The change to %pad is done in order to use a consistent output for the
dma_addr_t, which had a leading "0x" in two cases but not in the first
one.

printk interprets %pad as a pointer to a dma_addr_t and prints the
address, not the pointer to it, see Documentation/printk-formats.txt,
which lets you avoid the type cast as well as the 0x.

I understood now, I will check Documentation/printk-formats.txt.
Thanks for your explanation.


best regards,
Tiffany

	Arnd