This is a note to let you know that I've just added the patch titled gpu: ipu-v3: Fix dev_dbg frequency output to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: gpu-ipu-v3-fix-dev_dbg-frequency-output.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 011ed684c8532062a3693751ce0308c2a89c8cc4 Author: Leo Ruan <tingquan.ruan@xxxxxxxxxxxx> Date: Mon Feb 7 16:14:11 2022 +0100 gpu: ipu-v3: Fix dev_dbg frequency output [ Upstream commit 070a88fd4a03f921b73a2059e97d55faaa447dab ] This commit corrects the printing of the IPU clock error percentage if it is between -0.1% to -0.9%. For example, if the pixel clock requested is 27.2 MHz but only 27.0 MHz can be achieved the deviation is -0.8%. But the fixed point math had a flaw and calculated error of 0.2%. Before: Clocks: IPU 270000000Hz DI 24716667Hz Needed 27200000Hz IPU clock can give 27000000 with divider 10, error 0.2% Want 27200000Hz IPU 270000000Hz DI 24716667Hz using IPU, 27000000Hz After: Clocks: IPU 270000000Hz DI 24716667Hz Needed 27200000Hz IPU clock can give 27000000 with divider 10, error -0.8% Want 27200000Hz IPU 270000000Hz DI 24716667Hz using IPU, 27000000Hz Signed-off-by: Leo Ruan <tingquan.ruan@xxxxxxxxxxxx> Signed-off-by: Mark Jonas <mark.jonas@xxxxxxxxxxxx> Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220207151411.5009-1-mark.jonas@xxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/ipu-v3/ipu-di.c b/drivers/gpu/ipu-v3/ipu-di.c index d2f1bd9d3deb..c498dc7d8838 100644 --- a/drivers/gpu/ipu-v3/ipu-di.c +++ b/drivers/gpu/ipu-v3/ipu-di.c @@ -460,8 +460,9 @@ static void ipu_di_config_clock(struct ipu_di *di, error = rate / (sig->mode.pixelclock / 1000); - dev_dbg(di->ipu->dev, " IPU clock can give %lu with divider %u, error %d.%u%%\n", - rate, div, (signed)(error - 1000) / 10, error % 10); + dev_dbg(di->ipu->dev, " IPU clock can give %lu with divider %u, error %c%d.%d%%\n", + rate, div, error < 1000 ? '-' : '+', + abs(error - 1000) / 10, abs(error - 1000) % 10); /* Allow a 1% error */ if (error < 1010 && error >= 990) {