pi3 WiFi slow when using HDMI

[devnull42]

I have recently bought a pi 3 starter kit ( http://www.mcmelectronics.com/product/R ... 83-16561RK ) and am having severe wifi speed issues.

The problem is: use of hdmi causes the wifi speed to drop significantly. Basically when theres updates to the screen wifi speed drops and when the image becomes static again wifi speed will raise back up.

The commands I used to test were 'busybox nc -l -p 4242|pv > /dev/null' on the pi and 'pv /dev/zero|busybox nc 192.168.0.2 4242' on the client, I also used iperf to double check, I got similar results with both.

The speeds I would see would stay around 3 MB/s when using a 2.4gz client and 5 MB/s when using a 5gz client. My screen would be on a bash prompt just after login and the speed would stay steady, buy when I start typing the speed would drop down to 0.2MB/s and stay under 1 MB/s, This also happens if I run kodi, or play a video with omxplayer. ssh also becomes very unresponsive when the speed drops.

If I set my tv to 1080p/24hz with '/opt/vc/bin/tvservice -e "CEA 32 HDMI"' the network speed would still drop but the effect would be way less. My guess is the bandwidth for HDMI and wifi is shared and when HDMI is getting used heavily theres not enough for wifi, setting HDMI to 24hz reduces hdmi bandwidth use by 60% and therefore theres more left for wifi, this is just a guess though.

If at any point I see my network speed drop I can turn off HDMI output with '/opt/vc/bin/tvservice -o' and my speed will instantly jump back up to normal.

I have searched the forums and the only thing ive found to help wifi issues is to disable powersave 'iwconfig wlan0 power off' but I havent noticed a difference when doing this in either speed or ping.

I have tried the above with Rasbian Lite, OSMC, Openelec, and Void Linux. I also tried using Wicd, Connman, and settiing up wpa_supplicant directly. Each distro and connection method produced exactly the same problem. Everything was a fresh install with very few modifications.

I tried with my keyboard and a flash drive plugged in and also with nothing plugged in doing everything over ssh, both ways made no difference. I also tried copying a big file from the microsd card because I read that the wifi is on the SDIO and shares bandwidth with the sd card, dont know if thats true, didnt cause any effect.

This problem makes watching online videos like youtube in HD impossible without buffering, or downloading anything while using kodi.

The only thing I have found that helps is '/opt/vc/bin/tvservice -e "CEA 32 HDMI"' but this only reduces the problem and doesnt get rid of it completely.

I would love to know if anyone else has the same problem as me or if I just got a dud, I have read alot of forum posts about wifi and no one has the same problem as me or they do and havent found the link between wifi and HDMI.

[jamesh]

The only thing that makes sense to me is that the HDMI cable is causing interference on the Wifi signal. Have you tried a different HDMI cable with better shielding?

[devnull42]

The only thing that makes sense to me is that the HDMI cable is causing interference on the Wifi signal. Have you tried a different HDMI cable with better shielding?

When I first read this I thought it would be crazy if it works, I have read many articles about all HDMI being the same ... guess thats not true.

I tried 4 different cables: long/skinny/thick/short, on both Rasbian Lite and Void Linux. Every cable seemed to have a different effect on the speed. 3 of them about the same.

After switching to the shortest/thickest cable I had there was a major improvement. Kodi slows the network when starting but it stays stable in the menus or playing a video. Omxplayer has no noticable effect on speed when playing a video. The weird thing is holding down spacebar or typing fast at the login prompt still reduces the network speed, up to 90% for the first few seconds then stabilizings around a 20% reduction (4MB/s instead of 5MB/s). Pressing keys fast while in kodi, omxplayer, or lxterminal produces a similar effect.

After switching to the new cable, using /opt/vc/bin/tvservice to switch to 24hz has no noticible effect, might help a little, hard to tell.

This fix makes the pi completely usuable for me now because I do most things over the network and dont use the keyboard much so thank you for the suggestion. I still hope a firmware update might be able to completely fix this issue, if thats even possible.

I wonder if other people are having similar issues because there are alot of forum posts about slow wifi speed, especially on the OSMC forums.

[chunck]

I too had issues with my WiFi. I guess you could call me an old noob and I haven't been really involved with computer for many years.

So, I got an MCM RPi3 kit a few weeks ago. I'm a Ham radio junkie and was planning on using it for digital modes hooked to an RS232 serial port on my radio. It worked fine when I first was testing it for function, but as I was trying to hook-up my radio through a USB to RS232 adapter I ran into problems. I'm trying to find a way to get that solved. In the mean time I'm using an old desktop that has a DB9 serial port.

Now I was initially using an old Compaq TFT5030 monitor with a cheap GE HDMI to VGA adapter and some old HP keyboard and mouse. I noticed a few days or so that the WiFi was dropping out. After a short period it was useless. I went to several forums and saw others having issues. I tried several of the recommended fixes and none worked.

Now, I had recently (within the last couple days) changed out the Compaq monitor for a Dell 207FPb with a USB hub and powered speakers that hang under it. Thought it would be nice to have a few more powered USB port and some amplified speakers on the Pi. Also I thought I could power the Pi from the USB on the monitor and have an on/off switch. It dawned on me that my issues slowly began after I swapped out the monitors. I tried going back to the wall-wart power supply from the kit, but the WiFi was still inop. So I went back to the Compaq monitor and all my WiFi issues disappeared.

I'm not sure if it has something to do with the normal functioning of the Dell monitor, or if that particular monitor has issues as it was a surplus buy. Moral of the story to me is "If it ain't broke, don't fix it".

4/27/16: I am having trouble again with WiFi. I have an error stating that there is a GnuTLS internal error, a problem with the TLS handshake. Fun fun fun...

[grock]

My raspi3 is having real issues. These issues are not isolated to just the onboard wifi, they extend to usb wifi as well; however, the usb wifi seems to be slightly more stable than the onboard wifi.

Power supply for my raspi3 is running off 2.4 amps, and before I was running off 1 amp without issues.

Normally I pass a lot of data through my raspi and use it as my primary workstation interface to many other systems so when I can't have my monitor plugged in I'm really upset. Last night I spent a lot of time wondering and researching what the hell happened.

Here is what I've concluded and looks like others here have similar issues.

If I use the hdmi my wifi (wlan0) will not stay connected.
upon booting up
ifconfig shows no wlan0.

if I bring up the card manually it might stay up until I starting passing data then nothing gets through.
When the issue first starts, icmp (pings) become very slow, 1500+ms response.
Then the unknown host errors or nothing returns during the ping.
If dmesg I see errors similar to other users but red in color. The wifi card attempts to reset the connection.
I can manually bring it down using ifdown wlan0 then ifup wlan0 and sometimes it can't get an IP address from the dhcp server, so I try ifup wlan0 again. If it happens to get the IP address immediately after I start trying to connect to another system the same behavior occurs.

Problems seems to effect the bluetooth devices as well. I notice frequently dropped connection between keyboard and raspi, when trying to bring up the wlan0.

I updated the kernel and drivers this morning hoping the update would fix things.

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apt update; apt dist-upgrade; rpi-update

boot directory shows the updates.
/boot/

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total 20M
-rwxr-xr-x 1 root root  14K Aug  7 11:48 bcm2708-rpi-b.dtb
-rwxr-xr-x 1 root root  14K Aug  7 11:48 bcm2708-rpi-b-plus.dtb
-rwxr-xr-x 1 root root  13K Aug  7 11:48 bcm2708-rpi-cm.dtb
-rwxr-xr-x 1 root root  15K Aug  7 11:48 bcm2709-rpi-2-b.dtb
-rwxr-xr-x 1 root root  16K Aug  7 11:48 bcm2710-rpi-3-b.dtb
-rwxr-xr-x 1 root root  18K Aug  7 11:48 bootcode.bin
-rwxr-xr-x 1 root root  174 Apr 11 21:50 cmdline.txt
-rwxr-xr-x 1 root root  136 Apr  2 14:43 cmdline.txt.orig
-rwxr-xr-x 1 root root  174 Apr 11 21:50 cmdline.txt.usb.main.drive
-rwxr-xr-x 1 root root  174 Apr 11 21:50 cmdline.txt.usb.sda1
-rwxr-xr-x 1 root root 1.7K Aug  7 01:09 config.txt
-rwxr-xr-x 1 root root  19K Jul 19 00:12 COPYING.linux
-rwxr-xr-x 1 root root 2.5K Aug  7 11:48 fixup_cd.dat
-rwxr-xr-x 1 root root 6.4K Aug  7 11:48 fixup.dat
-rwxr-xr-x 1 root root 9.5K Aug  7 11:48 fixup_db.dat
-rwxr-xr-x 1 root root 9.5K Aug  7 11:48 fixup_x.dat
-rwxr-xr-x 1 root root  103 Mar 18 01:16 issue.txt
-rwxr-xr-x 1 root root 4.1M Aug  7 11:48 kernel7.img
-rwxr-xr-x 1 root root 4.0M Aug  7 11:48 kernel.img
-rwxr-xr-x 1 root root 1.5K Jul 19 00:12 LICENCE.broadcom
-rwxr-xr-x 1 root root  19K Mar 18 01:16 LICENSE.oracle
drwxr-xr-x 2 root root 8.0K Aug  7 11:48 overlays
-rwxr-xr-x 1 root root 605K Aug  7 11:48 start_cd.elf
-rwxr-xr-x 1 root root 4.8M Aug  7 11:48 start_db.elf
-rwxr-xr-x 1 root root 2.7M Aug  7 11:48 start.elf
-rwxr-xr-x 1 root root 3.8M Aug  7 11:48 start_x.elf

everything in the overlay directory is from august 7.

Prior to updating kernel and drivers I've installed minicom last night the system just can't stay connected. Up until last night I had solid uptime of 14 days with what seemed like perfect throughput.
Just before that 14 day run I had some problems and I was searching around for a solution. I thought it was just where my raspi was sitting in a radio signal vortex black hole.

I've searched for too long and found no solution to this issue.

I've got another raspi3 and I will one more time test if the same issue exist when connecting using hdmi cable to monitor.

I'm running raspbian jessi.

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uname -a
 4.4.16-v7+ #899 SMP Thu Jul 28 12:40:33 BST 2016 armv7l GNU/Linux

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cat /proc/version
Linux version 4.4.16-v7+ (dc4@dc4-XPS13-9333) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0-88-g8460611) ) #899 SMP Thu Jul 28 12:40:33 BST 2016

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cat /etc/issue
Raspbian GNU/Linux 8 \n \l

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lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 8.0 (jessie)
Release:        8.0
Codename:       jessie

I wish there was a valid way I could determine if my hardware is not broken. This just seems like I have a dud on my hands. I will test with my other raspi3 to check if I get the same issue.

[grock]

This is a follow up to my recent last post.

The issues I'm having using hdmi cable is caused by a specific monitor. My raspi3 is functioning fine as long as I don't plug it into that specific Dell Monitor. 2001FP monitor seems to be the exact cause. I'm not sure why this is happening or why it suddenly started getting worse.

I've verified its not the hdmi cable. Tried 2 different cables (although same manufacture).
Using the raspi3 with my philips monitor works just fine.

... so although I found the cause I have no idea how to fix this.

If anyone else does please let me know.

[grock]

This is another update.

Sometime after I edited the last post and the morning my raspi3 wifi went down, and experienced all the same symptoms I described before. Back online with my raspi2B+.
At this point I'm classifying my raspi3 device as a dud, unless someone here at the raspberry pi foundation can say otherwise.

Here is part of the dmesg output

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[69396.062848] ------------[ cut here ]------------
[69396.062915] WARNING: CPU: 0 PID: 26406 at net/wireless/sme.c:981 cfg80211_connect+0x234/0x588 [cfg80211]()
[69396.062920] Modules linked in: uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core v4l2_common snd_usb_audio snd_hwdep snd_usbmidi_lib videodev media snd_seq_dummy snd_seq_midi snd_rawmidi snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device rfcomm evdev joydev hidp bnep hci_uart btbcm bluetooth binfmt_misc sg brcmfmac brcmutil cfg80211 rfkill snd_bcm2835 snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd bcm2835_gpiomem bcm2835_wdt uio_pdrv_genirq uio fuse ipv6
[69396.063017] CPU: 0 PID: 26406 Comm: iwconfig Tainted: G        W       4.4.16-v7+ #899
[69396.063022] Hardware name: BCM2709
[69396.063044] [<80018724>] (unwind_backtrace) from [<80014058>] (show_stack+0x20/0x24)
[69396.063057] [<80014058>] (show_stack) from [<80320884>] (dump_stack+0xd4/0x118)
[69396.063070] [<80320884>] (dump_stack) from [<80025300>] (warn_slowpath_common+0x98/0xc8)
[69396.063082] [<80025300>] (warn_slowpath_common) from [<800253ec>] (warn_slowpath_null+0x2c/0x34)
[69396.063127] [<800253ec>] (warn_slowpath_null) from [<7f14cad4>] (cfg80211_connect+0x234/0x588 [cfg80211])
[69396.063207] [<7f14cad4>] (cfg80211_connect [cfg80211]) from [<7f165c5c>] (cfg80211_mgd_wext_connect+0x114/0x180 [cfg80211])
[69396.063287] [<7f165c5c>] (cfg80211_mgd_wext_connect [cfg80211]) from [<7f16624c>] (cfg80211_mgd_wext_siwap+0x104/0x190 [cfg80211])
[69396.063367] [<7f16624c>] (cfg80211_mgd_wext_siwap [cfg80211]) from [<7f165360>] (cfg80211_wext_siwap+0xb4/0x1e4 [cfg80211])
[69396.063415] [<7f165360>] (cfg80211_wext_siwap [cfg80211]) from [<805addf8>] (ioctl_standard_call+0x6c/0x4b4)
[69396.063427] [<805addf8>] (ioctl_standard_call) from [<805ae538>] (wext_handle_ioctl+0x1b8/0x23c)
[69396.063438] [<805ae538>] (wext_handle_ioctl) from [<804ee090>] (dev_ioctl+0x53c/0x800)
[69396.063451] [<804ee090>] (dev_ioctl) from [<804b71c4>] (sock_ioctl+0x12c/0x2b0)
[69396.063462] [<804b71c4>] (sock_ioctl) from [<801694c8>] (do_vfs_ioctl+0x424/0x614)
[69396.063472] [<801694c8>] (do_vfs_ioctl) from [<801696fc>] (SyS_ioctl+0x44/0x6c)
[69396.063482] [<801696fc>] (SyS_ioctl) from [<8000fb40>] (ret_fast_syscall+0x0/0x1c)
[69396.063488] ---[ end trace e0fc9f999cb2373a ]---
[69396.200565] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[69399.965657] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[69399.965685] brcmfmac: power management disabled
[69399.968428] brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code
[69399.968443] cfg80211: World regulatory domain updated:
[69399.968448] cfg80211:  DFS Master region: unset
[69399.968454] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[69399.968461] cfg80211:   (2402000 KHz - 2472000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A)
[69399.968468] cfg80211:   (2457000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A)
[69399.968474] cfg80211:   (2474000 KHz - 2494000 KHz @ 20000 KHz), (N/A, 2000 mBm), (N/A)
[69399.968482] cfg80211:   (5170000 KHz - 5250000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (N/A)
[69399.968490] cfg80211:   (5250000 KHz - 5330000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (0 s)
[69399.968496] cfg80211:   (5490000 KHz - 5730000 KHz @ 160000 KHz), (N/A, 2000 mBm), (0 s)
[69399.968502] cfg80211:   (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 2000 mBm), (N/A)
[69399.968509] cfg80211:   (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 0 mBm), (N/A)
[69399.995033] cfg80211: Regulatory domain changed to country: US
[69399.995046] cfg80211:  DFS Master region: FCC
[69399.995052] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[69399.995059] cfg80211:   (2402000 KHz - 2472000 KHz @ 40000 KHz), (N/A, 3000 mBm), (N/A)
[69399.995067] cfg80211:   (5170000 KHz - 5250000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 1700 mBm), (N/A)
[69399.995075] cfg80211:   (5250000 KHz - 5330000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2300 mBm), (0 s)
[69399.995081] cfg80211:   (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 3000 mBm), (N/A)
[69399.995089] cfg80211:   (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 4000 mBm), (N/A)
[69400.088246] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[69400.153654] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[69400.153875] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[69594.406905] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[69594.406943] brcmfmac: power management disabled
[69595.799762] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[69595.799825] brcmfmac: power management disabled
[69595.993956] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[69596.065517] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[69596.065991] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[69596.749969] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[69596.750038] brcmfmac: power management disabled

if any other logs will help let me know.


Testing using a raspi 1 B+ with a usb wifi doesn't have this problem at all.
Testing using a raspi 2 B with a usb wifi doesn't have this problem at all.

[vorburger]

I've hit the same problem... Thank you for pointing out the relationship with HDMI; I'm seeing this too (and it would never have occurred to me to think this is related, but as far as I can see on mine it does seem to not be happening with no HDMI cable; how weird).

I've opened https://bugzilla.kernel.org/show_bug.cgi?id=153471 to see if anything can be done about eventually getting this fixed.

[grock]

I'm still trying to determine if this is with all raspi3 devices, or if I just have a dud. I'm working an RMA now and in the process of ordering a new raspi3.

I hope we find out something because it doesn't seem right we can't have video output to hdmi and networking.

[grock]

I resolved my issue by sending my raspberry pi 3 back using the RMA process.

I've just installed my replacement and I'm not seeing any problems with the wifi card while connected and using the hdmi cable.

Its my opinion and I'm going to test a bit more, that a batch of raspberry pi devices have some defect. I say this because I ordered 3 of them and all 3 of them have the issue however this new one doesn't.

I haven't used a fresh image. I simply took the sd card out of the defective device and put it in the replacement device. So excluding any regular updates to the device nothing has changed except the hardware.

I'll post the results after the test is completed.

[sandrokan750]

I have similar issues.

I don't think it is not related to a dud device: I have the exact same problem with 3 different devices from 3 different shops bought some months apart.

All 3 works perfectly it I plug them to my TV, but the wifi is not working when I plug them into the HT (ampli+projector) in a different room (btw, much closer to the wifi router).

When the hdmi cable is plugged in but the ampli is off, then the wifi is super fast. As soon as I switch on the amplifier, the wifi disconnects (with some luck it stays connected for few seconds, very slow, then dies).


I have completely disabled all HDMI-CEC on both the Raspberry and the Amplifier, but still some disturbance goes from the ampli to the PI via the HDMI cable, making the wifi unusable.

Does anybody have some update on this?

[xparks]

I received my new Raspberry Pi 3 Model B a few days ago, and I want to report that I am experiencing this exact problem with HDMI interfering with wifi. My pi is connected through an HDMI-to-DVI adapter, then through a DVI-to-DVI cable to a Dell U2412M monitor. When the HDMI port is used, the wifi is flaky, sometimes it does not connect. When it does connect, the latency is wildly erratic. Ping times to my router can be anywhere between 10ms to 2000ms. Sometimes everything pauses for several seconds, then a whole bunch of packets arrive. Sometimes, the packets are dropped entirely. When I put my hand on the external case, sometimes it becomes better, but not always. If I physically move the Pi into different positions and orientations, sometimes that helps but not always. If I unplug the HDMI adapter, the ping latency suddenly goes down to 4-7ms. When I turn off wifi and plug my ethernet cable, the network works consistently, even with the HDMI port connected, and the ping time drops to sub-milliseconds (0.2-0.5ms). It seems like some sort of EM interference between the HDMI port and the wifi. I'm going to purchase a direct HDMI-to-DVI cable and see if that makes a difference.

[ManuelJorge]

Trust me: if you buy a USB-WiFi dongle and a USB male-female extender (10-20 cm would do) everything will be fine. I don't think it's the HDMI that interferes with the WiFi, rather the opposite: it's the wifi's radio that interferes with the rpi...

[davidcoton]

IIRC, in another thread (which I can't find ATM) a similar problem was found to be due to a poor HDMI cable, which was radiating enough RF at the WiFi frequency to block the Pi's onboard WiFi. A poor HDMI cable also caused problems with early EMC testing of the Pi.

[MaxK1]

Earlier in this topic, Jamesh reported bad HDMI cable

[johnirak]

Would that be possible to damage a raspberry pi with a bad hdmi cable?
I have 4 raspberies until now with the same problem. I got the under voltage warning on the screen permanently although I use the official power adapter and I measure 4.9-5.0 volts on the raspberry. The USB,ethernet and wifi are all unusable and there is not way to fix them. Also I measured the voltage on all the test points and compared the values with a new raspberry but I didn't find any differences.
I was using them with OSMC and the only things I had attached on them were the hdmi cable and a usb dongle for a wireless keyboard.

[davidcoton]

Has the red PoWeR LED gone off?
Does it come back on if you disconnect the HDMI cable?
Does it stay on if you disconnect the monitor but connect the cable to the Pi?
Same for disconnecting USB peripheals.
There is a fault that disables USB power, but you would be incredibly unlucky to have that on four Pis, unless you have plugged the same faulty cable or peripheral into each Pi.

[johnirak]

The red led is on. The green led is constantly off with or without the hdmi cable and usb peripherals.

[runboy93]

Get official HDMI cable, includes better plating (better wifi usage), or buy WiFi dongle.