From: "Ing. Josua Mayer" <josua.mayer@jm0.eu>
To: matrandg@cisco.com, mchehab@kernel.org
Cc: linux-media@vger.kernel.org
Subject: Re: [BUG] tc358743: division by zero
Date: Wed, 9 Jun 2021 17:08:45 +0200 [thread overview]
Message-ID: <19a143de-818d-4c21-94c1-f4ebf57e3802@jm0.eu> (raw)
In-Reply-To: <427466e4-1b6f-f7c3-3d5e-89c7a7f2ec79@jm0.eu>
[-- Attachment #1: Type: text/plain, Size: 4665 bytes --]
and I forgot about the promised dts :( .. I am realyl sorry for spamming
your mailbox like this ...
Am 09.06.21 um 17:07 schrieb Ing. Josua Mayer:
> Dear Maintainers,
>
> During my attempts at capturing HDMI via the csi-2 port on i.MX6
> HummingBoard, I triggered a division by zero in
> tc358743_num_csi_lanes_needed!
> I am running Debian testing, with linux 5.10.40 - built from debian
> sources with the tc358743 driver enabled:
> Linux sr-imx6 5.10.0-7-armmp #1 SMP Debian 5.10.40-2 (2021-05-29) armv7l
> GNU/Linux
>
> The crash is triggered from userspace as I execute:
> media-ctl -l "'tc358743 0-000f':0->'imx6-mipi-csi2':0[1]"
> media-ctl -l "'imx6-mipi-csi2':1->'ipu1_csi0_mux':0[1]"
> media-ctl -l "'ipu1_csi0_mux':2->'ipu1_csi0':0[1]"
> media-ctl -l "'ipu1_csi0':2->'ipu1_csi0 capture':0[1]"
> v4l2-ctl -d /dev/v4l-subdev7 --set-edid=file=tc358743-edid.hex && sleep 1
> v4l2-ctl -d /dev/v4l-subdev7 --set-dv-bt-timings query && sleep 1
>
> [ 60.985439] Division by zero in kernel.
> [ 60.989333] CPU: 1 PID: 395 Comm: v4l2-ctl Tainted: G WC E
> 5.10.0-7-armmp #1 Debian 5.10.40-2
> [ 60.998904] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
> [ 61.005438] Backtrace:
> [ 61.007911] [<c0cf1fe8>] (dump_backtrace) from [<c0cf2394>]
> (show_stack+0x20/0x24)
> [ 61.015489] r7:00000018 r6:600b0013 r5:00000000 r4:c14cdc90
> [ 61.021162] [<c0cf2374>] (show_stack) from [<c0cf74c4>]
> (dump_stack+0xc8/0xdc)
> [ 61.028394] [<c0cf73fc>] (dump_stack) from [<c0cf216c>]
> (__div0+0x24/0x28)
> [ 61.035276] r7:00000018 r6:034bc000 r5:c1f67890 r4:4f1a0000
> [ 61.040951] [<c0cf2148>] (__div0) from [<c07b1254>] (Ldiv0+0x8/0x10)
> [ 61.047336] [<bf412000>] (tc358743_num_csi_lanes_needed [tc358743])
> from [<bf412a44>] (tc358743_set_csi+0x1c/0x3f0 [tc358743])
> [ 61.058734] r9:00000000 r8:c2b8b400 r7:c1f67a59 r6:bf419380
> r5:c1f679e8 r4:c1f67890
> [ 61.066495] [<bf412a28>] (tc358743_set_csi [tc358743]) from
> [<bf413f64>] (tc358743_s_dv_timings+0x104/0x1a8 [tc358743])
> [ 61.077283] r7:c1f67a59 r6:bf419380 r5:c1f679e8 r4:c1f67890
> [ 61.082961] [<bf413e60>] (tc358743_s_dv_timings [tc358743]) from
> [<c0a79fd4>] (subdev_do_ioctl+0x430/0xd0c)
> [ 61.092708] r7:c1f67890 r6:c2ea0780 r5:c2d91c00 r4:c0845657
> [ 61.098376] [<c0a79ba4>] (subdev_do_ioctl) from [<c0a7a934>]
> (subdev_do_ioctl_lock+0x84/0xb4)
> [ 61.106909] r10:c2d91c00 r9:bea08dec r8:c0845657 r7:00000000
> r6:c2d91c00 r5:c2ea0780
> [ 61.114741] r4:c2e35000
> [ 61.117294] [<c0a7a8b0>] (subdev_do_ioctl_lock) from [<c0a6c4b4>]
> (video_usercopy+0x190/0x674)
> [ 61.125913] r9:bea08dec r8:c2d91c00 r7:bea08dec r6:c0845657
> r5:00000000 r4:c0845657
> [ 61.133668] [<c0a6c324>] (video_usercopy) from [<c0a79254>]
> (subdev_ioctl+0x20/0x24)
> [ 61.141419] r10:c30372a8 r9:00000003 r8:c2ea0780 r7:bea08dec
> r6:c2ea0780 r5:00000000
> [ 61.149251] r4:c0a79234
> [ 61.151797] [<c0a79234>] (subdev_ioctl) from [<c0a64920>]
> (v4l2_ioctl+0x4c/0x60)
> [ 61.159207] [<c0a648d4>] (v4l2_ioctl) from [<c05a90ac>]
> (sys_ioctl+0x130/0xa74)
> [ 61.166520] r5:00000000 r4:c0845657
> [ 61.170107] [<c05a8f7c>] (sys_ioctl) from [<c03000c0>]
> (ret_fast_syscall+0x0/0x54)
> [ 61.177681] Exception stack(0xc48adfa8 to 0xc48adff0)
> [ 61.182742] dfa0: 005023a4 004dad3c 00000003
> c0845657 bea08dec 00000000
> [ 61.190927] dfc0: 005023a4 004dad3c 00000003 00000036 0050c808
> bea09494 bea08fa0 00000000
> [ 61.199109] dfe0: 00500df8 bea08d2c 004a635d b6cde418
> [ 61.204169] r10:00000036 r9:c48ac000 r8:c03002c4 r7:00000036
> r6:00000003 r5:004dad3c
> [ 61.212000] r4:005023a4
>
> I am attaching the device-tree changes as a file for reference. Any
> ideas what is happening here?
>
> I can see 2 divisions:
> 1. pdata->refclk_hz / pdata->pll_prd
> 2. DIV_ROUND_UP(bps, bps_pr_lane)
>
> 1. should never be 0, since it is initialized during probe and then
> never changed
>
> 2. see how the divisor can be 0
> pdata->refclk_hz / pdata->pll_prd is the inversion of how pll_prd is
> calculated, and should equal to 6MHz from probe.
> pll_fbd is also set in probe: pll_fbd = bps_pr_lane / refclk_hz * pll_prd
> As I have specified a link-frequency of 594MHz, that produces:
> bps_pr_lane = 2 * 594MHz
> pll_fbd = 2 * 594MHz / 27MHz * (27MHz / 6MHz) = 2 * 594MHz / 6MHz = 198
>
> Apparently from initialization, the division by zero can not occur :(
> (unless I made a mistake here).
>
> Thank you for reading this far!
> Yours sincerely
> Josua Mayer
[-- Attachment #2: 0001-ARM-dts-imx6qdl-hummingboard-attach-tc358743-capture.patch --]
[-- Type: text/x-patch, Size: 2252 bytes --]
From 84b058f6677cda666ae19b5717c8386d63778647 Mon Sep 17 00:00:00 2001
From: Josua Mayer <josua.mayer@jm0.eu>
Date: Wed, 9 Jun 2021 16:43:32 +0200
Subject: [PATCH] ARM: dts: imx6qdl-hummingboard: attach tc358743 capture
device
---
arch/arm/boot/dts/imx6qdl-hummingboard.dtsi | 48 +++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/arch/arm/boot/dts/imx6qdl-hummingboard.dtsi b/arch/arm/boot/dts/imx6qdl-hummingboard.dtsi
index 2ffb21dd89f2..f49143344299 100644
--- a/arch/arm/boot/dts/imx6qdl-hummingboard.dtsi
+++ b/arch/arm/boot/dts/imx6qdl-hummingboard.dtsi
@@ -142,6 +142,12 @@ sound-spdif {
spdif-controller = <&spdif>;
spdif-out;
};
+
+ tc358743_clk: bridge-clk {
+ compatible = "fixed-clock";
+ #clock-cells = <0>;
+ clock-frequency = <27000000>;
+ };
};
&audmux {
@@ -203,6 +209,27 @@ sgtl5000: codec@a {
VDDA-supply = <&v_3v2>;
VDDIO-supply = <&v_3v2>;
};
+
+ tc358743: capture@f {
+ compatible = "toshiba,tc358743";
+ reg = <0x0f>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_hummingboard_mipi>;
+ //clocks = <&clks IMX6QDL_CLK_CKO2>;
+ clocks = <&tc358743_clk>;
+ clock-names = "refclk";
+ reset-gpios = <&gpio2 10 GPIO_ACTIVE_LOW>;
+
+ port {
+ tc358743_out: endpoint {
+ remote-endpoint = <&mipi_csi2_in>;
+ data-lanes = <1 2>;
+ clock-lanes = <0>;
+ clock-noncontinuous;
+ link-frequencies = /bits/ 64 <594000000>;
+ };
+ };
+ };
};
&i2c2 {
@@ -247,6 +274,13 @@ MX6QDL_PAD_KEY_ROW3__I2C2_SDA 0x4001b8b1
>;
};
+ pinctrl_hummingboard_mipi: hummingboard_mipi {
+ fsl,pins = <
+ MX6QDL_PAD_SD4_DAT2__GPIO2_IO10 0x4001b8b1
+ MX6QDL_PAD_NANDF_CS2__CCM_CLKO2 0x130b0
+ >;
+ };
+
pinctrl_hummingboard_pcie_reset: hummingboard-pcie-reset {
fsl,pins = <
MX6QDL_PAD_EIM_DA4__GPIO3_IO04 0x1b0b1
@@ -310,6 +344,20 @@ MX6QDL_PAD_DISP0_DAT9__GPIO4_IO30 0x1b0b0
};
};
+&mipi_csi {
+ status = "okay";
+
+ port {
+ mipi_csi2_in: endpoint {
+ remote-endpoint = <&tc358743_out>;
+ data-lanes = <1 2 3 4>;
+ clock-lanes = <0>;
+ clock-noncontinuous;
+ link-frequencies = /bits/ 64 <297000000>;
+ };
+ };
+};
+
&pcie {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_hummingboard_pcie_reset>;
--
2.31.1
next prev parent reply other threads:[~2021-06-09 15:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 15:07 [BUG] tc358743: division by zero Ing. Josua Mayer
2021-06-09 15:08 ` Ing. Josua Mayer [this message]
2021-06-09 17:08 ` Ing. Josua Mayer
2021-06-09 17:27 ` Dave Stevenson
2021-06-21 14:58 ` Ing. Josua Mayer
2021-06-22 20:33 ` [PATCH] media: tc358743: fix missing return of error code in tc358743_probe_of Josua Mayer
2021-06-23 10:05 ` Dave Stevenson
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