Messages in this thread |  | | From | Jammy Huang <> | | Subject | RE: [PATCH] media: aspeed: Fix dram hang at res-change | | Date | Mon, 1 Dec 2025 01:34:25 +0000 |
| |
Hi Wang,
Thanks for your feedback.
Regards, Jammy Huang
> > > > Dram hang could happen in the steps below: > > 1. start capture/compression > > 2. out-of-lock watchdog raise irq because of res-change. > > 3. aspeed_video_irq_res_change do clk-off > > > > At step3, capture/compression could be not accomplished yet. If > > clk-off in the middle of video operation, dram controller could hang at > ast2500. > > > > Use reset rather than clk-off/on to avoid this problem. > > > > Signed-off-by: Jammy Huang <jammy_huang@aspeedtech.com> > > --- > > On Aspeed KVM testing, we found it could lead to dram-hang if > > res-change. Although the issue rarely happens, the impact is serious. > > Capturing and compressing the video stream takes longer than the video > engine’s idle period. Sorry, but this is not what I mean. The issue happens because video engine's clk is turned off during capture/compression.
> If this is not the intended behavior, please increase the frame rate. This makes > resolution switches more prone to happen when the video engine is working. > However, according to your email, this issue rarely occurs. Is there a similar > issue on the AST2600 SoC? Increase frame rate would not helpful. This is a video compression engine. The time taken for each frame's capture/compression is the same. The way to reproduce this issue we did is continuously resolution-switch.
> > > > > To avoid this issue, we use reset only rathar than clk-off/on in > > res-change to avoid this issue. > > --- > > drivers/media/platform/aspeed/aspeed-video.c | 22 > > +++++++++++++++++++--- > > 1 file changed, 19 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/media/platform/aspeed/aspeed-video.c > > b/drivers/media/platform/aspeed/aspeed-video.c > > index b83e432452..41cb96f601 100644 > > --- a/drivers/media/platform/aspeed/aspeed-video.c > > +++ b/drivers/media/platform/aspeed/aspeed-video.c > > @@ -26,6 +26,7 @@ > > #include <linux/workqueue.h> > > #include <linux/debugfs.h> > > #include <linux/ktime.h> > > +#include <linux/reset.h> > > #include <linux/regmap.h> > > #include <linux/mfd/syscon.h> > > #include <media/v4l2-ctrls.h> > > @@ -310,6 +311,7 @@ struct aspeed_video { > > void __iomem *base; > > struct clk *eclk; > > struct clk *vclk; > > + struct reset_control *reset; > > > > struct device *dev; > > struct v4l2_ctrl_handler ctrl_handler; @@ -720,6 +722,13 @@ static > > void aspeed_video_on(struct aspeed_video *video) > > set_bit(VIDEO_CLOCKS_ON, &video->flags); } > > > > +static void aspeed_video_reset(struct aspeed_video *v) { > > + reset_control_assert(v->reset); > > + usleep_range(100, 150); > > + reset_control_deassert(v->reset); > > +} > > + > > static void aspeed_video_bufs_done(struct aspeed_video *video, > > enum vb2_buffer_state state) > > { > > @@ -742,7 +751,9 @@ static void aspeed_video_irq_res_change(struct > > aspeed_video *video, ulong delay) > > > > video->v4l2_input_status = V4L2_IN_ST_NO_SIGNAL; > > > > - aspeed_video_off(video); > > + aspeed_video_write(video, VE_INTERRUPT_CTRL, 0); > > + aspeed_video_write(video, VE_INTERRUPT_STATUS, 0xffffffff); > > + aspeed_video_reset(video); > > aspeed_video_bufs_done(video, VB2_BUF_STATE_ERROR); > > > > schedule_delayed_work(&video->res_work, delay); @@ -1984,8 +1995,7 > > @@ static void aspeed_video_stop_streaming(struct vb2_queue *q) > > * Need to force stop any DMA and try and get HW into a good > > * state for future calls to start streaming again. > > */ > > - aspeed_video_off(video); > > - aspeed_video_on(video); > > + aspeed_video_reset(video); > > > > aspeed_video_init_regs(video); > > > > @@ -2230,6 +2240,12 @@ static int aspeed_video_init(struct aspeed_video > *video) > > } > > dev_info(video->dev, "irq %d\n", irq); > > > > + video->reset = devm_reset_control_get(dev, NULL); > > + if (IS_ERR(video->reset)) { > > + dev_err(dev, "Unable to get reset\n"); > > + return PTR_ERR(video->reset); > > + } > > + > > video->eclk = devm_clk_get(dev, "eclk"); > > if (IS_ERR(video->eclk)) { > > dev_err(dev, "Unable to get ECLK\n"); > > > > --- > > base-commit: ac3fd01e4c1efce8f2c054cdeb2ddd2fc0fb150d > > change-id: 20251124-video_dram_reset-c531f6ba573f > > > > Best regards, > > -- > > Jammy Huang <jammy_huang@aspeedtech.com> > > > > > > > 信息安全声明:本邮件包含信息归发件人所在组织所有,发件人所在组织对 > 该邮件拥有所有权利。请接收者注意保密,未经发件人书面许可,不得向任何 > 第三方组织和个人透露本邮件所含信息。 > Information Security Notice: The information contained in this mail is solely > property of the sender's organization.This mail communication is > confidential.Recipients named above are obligated to maintain secrecy and are > not permitted to disclose the contents of this communication to others.
|  |