Re: [PATCH v5 0/7] Add AMD ISP4 driver

["Du, Bin" <bin.du@amd.com>]

On 11/11/2025 5:05 PM, Sultan Alsawaf wrote:

> On Mon, Nov 10, 2025 at 05:46:28PM +0800, Du, Bin wrote:
>> Thank you, Sultan, for your time, big effort, and constant support.
>> Apologies for my delayed reply for being occupied a little with other
>> matters.
>>
>> On 11/10/2025 4:33 PM, Sultan Alsawaf wrote:
>>> Hi Bin,
>>>
>>> On Wed, Nov 05, 2025 at 01:25:58AM -0800, Sultan Alsawaf wrote:
>>>> Hi Bin,
>>>>
>>>> To expedite review, I've attached a patch containing a bunch of fixes I've made
>>>> on top of v5. Most of my changes should be self-explanatory; feel free to ask
>>>> further about specific changes if you have any questions.
>>>>
>>>> I haven't had a chance to review all of the v4 -> v5 changes yet, but I figured
>>>> I should send what I've got so far.
>>>>
>>>> FYI, there is a regression in isp4if_dequeue_buffer() where the bufq lock isn't
>>>> protecting the list_del() anymore. I also checked the compiler output when using
>>>> guard() versus scoped_guard() in that function and there is no difference:
>>>>
>>>>     sha1sum:
>>>>     5652a0306da22ea741d80a9e03a787d0f71758a8  isp4_interface.o // guard()
>>>>     5652a0306da22ea741d80a9e03a787d0f71758a8  isp4_interface.o // scoped_guard()
>>>>
>>>> So guard() should be used there again, which I've done in my patch.
>>>>
>>>> I also have a few questions:
>>>>
>>>> 1. Does ISP FW provide a register interface to disable the IRQ? If so, it is
>>>>      faster to use that than using disable_irq_nosync() to disable the IRQ from
>>>>      the CPU's side.
>>>>
>>>> 2. When the IRQ is re-enabled in isp4sd_fw_resp_func(), is there anything
>>>>      beforehand to mask all pending interrupts from the ISP so that there isn't a
>>>>      bunch of stale interrupts firing as soon the IRQ is re-enabled?
>>>>
>>>> 3. Is there any risk of deadlock due to the stream kthread racing with the ISP
>>>>      when the ISP posts a new response _after_ the kthread determines there are no
>>>>      more new responses but _before_ the enable_irq() in isp4sd_fw_resp_func()?
>>>>
>>>> 4. Why are some lines much longer than before? It seems inconsistent that now
>>>>      there is a mix of several lines wrapped to 80 cols and many lines going
>>>>      beyond 80 cols. And there are multiple places where code is wrapped before
>>>>      reaching 80 cols even with lots of room left, specifically for cases where it
>>>>      wouldn't hurt readability to put more characters onto each line.
>>>
>>> I've attached a new, complete patch of changes to apply on top of v5. You may
>>> ignore the incomplete patch from my previous email and use the new one instead.
>>>
>>> I made many changes and also answered questions 1-3 myself.
>>>
>>> Please apply this on top of v5 and let me know if you have any questions.
>>>
>>
>> Sure, will review, apply and test your patch accordingly. Your contribution
>> is greatly appreciated, will let you know if there is any question or
>> problem.
>>
>>> BTW, I noticed a strange regression in v5 even without any of my changes: every
>>> time you use cheese after using it one time, the video will freeze after 30-60
>>> seconds with this message printed to dmesg:
>>>     [ 2032.716559] amd_isp_capture amd_isp_capture: -><- fail respid unknown respid(0x30002)
>>>
>>> And the video never unfreezes. I haven't found the cause for the regression yet;
>>> can you try to reproduce it?
>>>
>>
>> Really weird, we don't see this issue either in dev or QA test. Is it 100%
>> reproducible and any other fail or err in the log?
> 
> Yes, it's 100% reproducible. There's no other message in dmesg, only that one.
> 
> Sometimes there is a stop stream error when I close cheese after it froze:
> 
>    [  656.540307] amd_isp_capture amd_isp_capture: fail to disable stream
>    [  657.046633] amd_isp_capture amd_isp_capture: fail to stop steam
>    [  657.047224] amd_isp_capture amd_isp_capture: disabling streaming failed (-110)
> 
> When I revert to v4 I cannot reproduce it at all. It seems to be something in
> v4 -> v5 that is not fixed by any of my changes.
> 

Hi Sultan, could you please try following modifications on top of v5 to 
see if it helps?

diff --git a/drivers/media/platform/amd/isp4/isp4_fw_cmd_resp.h 
b/drivers/media/platform/amd/isp4/isp4_fw_cmd_resp.h
index 39c2265121f9..d571b3873edb 100644
--- a/drivers/media/platform/amd/isp4/isp4_fw_cmd_resp.h
+++ b/drivers/media/platform/amd/isp4/isp4_fw_cmd_resp.h
@@ -97,7 +97,7 @@

#define ADDR_SPACE_TYPE_GPU_VA          4

-#define FW_MEMORY_POOL_SIZE             (200 * 1024 * 1024)
+#define FW_MEMORY_POOL_SIZE             (100 * 1024 * 1024)

/*
   * standard ISP mipicsi=>isp
diff --git a/drivers/media/platform/amd/isp4/isp4_subdev.c 
b/drivers/media/platform/amd/isp4/isp4_subdev.c
index 248d10076ae8..acbc80aa709e 100644
--- a/drivers/media/platform/amd/isp4/isp4_subdev.c
+++ b/drivers/media/platform/amd/isp4/isp4_subdev.c
@@ -697,7 +697,7 @@ static int isp4sd_stop_resp_proc_threads(struct 
isp4_subdev *isp_subdev)
         return 0;
}

-static int isp4sd_pwroff_and_deinit(struct isp4_subdev *isp_subdev)
+static int isp4sd_pwroff_and_deinit(struct isp4_subdev *isp_subdev, 
bool irq_enabled)
{
         struct isp4sd_sensor_info *sensor_info = &isp_subdev->sensor_info;
         unsigned int perf_state = ISP4SD_PERFORMANCE_STATE_LOW;
@@ -716,8 +716,9 @@ static int isp4sd_pwroff_and_deinit(struct 
isp4_subdev *isp_subdev)
                 return 0;
         }

-       for (int i = 0; i < ISP4SD_MAX_FW_RESP_STREAM_NUM; i++)
-               disable_irq(isp_subdev->irq[i]);
+       if (irq_enabled)
+               for (int i = 0; i < ISP4SD_MAX_FW_RESP_STREAM_NUM; i++)
+                       disable_irq(isp_subdev->irq[i]);

         isp4sd_stop_resp_proc_threads(isp_subdev);
         dev_dbg(dev, "isp_subdev stop resp proc streads suc");
@@ -813,7 +814,7 @@ static int isp4sd_pwron_and_init(struct isp4_subdev 
*isp_subdev)

         return 0;
err_unlock_and_close:
-       isp4sd_pwroff_and_deinit(isp_subdev);
+       isp4sd_pwroff_and_deinit(isp_subdev, false);
         return -EINVAL;
}

@@ -985,7 +986,7 @@ static int isp4sd_set_power(struct v4l2_subdev *sd, 
int on)
         if (on)
                 return isp4sd_pwron_and_init(isp_subdev);
         else
-               return isp4sd_pwroff_and_deinit(isp_subdev);
+               return isp4sd_pwroff_and_deinit(isp_subdev, true);
}

static const struct v4l2_subdev_core_ops isp4sd_core_ops = {


On the other hand, please also add the patch in amdgpu which sets *bo to 
NULL in isp_kernel_buffer_alloc() which you mentioned in another thread.

> I will try to identify the cause this week.
> 
> Sultan

-- 
Regards,
Bin