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by jdb
Tue Aug 04, 2020 9:32 am
Forum: Advanced users
Topic: Pi4 USB messages dropping
Replies: 12
Views: 692

Re: Pi4 USB messages dropping

Either your driver is doing something a bit weird or the log is incomplete. I see thousands of interrupt URB submissions, but with no corresponding events to say that they've completed. Reported events only start hundreds of seconds later, but I can see the dequeue pointers for the endpoint advancin...
by jdb
Mon Aug 03, 2020 9:13 pm
Forum: Advanced users
Topic: Possible to replace RPi4 54MHz crystal with different frequency?
Replies: 12
Views: 710

Re: Possible to replace RPi4 54MHz crystal with different frequency?

The chip won't work with a different crystal frequency. There are fixed divider ratios in hardware scattered across the chip that expect 54MHz to be distributed to various PHYs. Notably, SDRAM won't work. If you need jitter-free I2S clocks, then use an I2S codec that can drive the clock as a master ...
by jdb
Mon Aug 03, 2020 2:18 pm
Forum: Advanced users
Topic: Pi4 USB messages dropping
Replies: 12
Views: 692

Re: Pi4 USB messages dropping

Can you capture an xhci trace up until the point where the firmware reports the failure using the method in the linked post?

viewtopic.php?t=250990&start=75#p1560630
by jdb
Sun Aug 02, 2020 5:58 pm
Forum: Troubleshooting
Topic: Issues using full speed devices with USB 3.0 hubs
Replies: 2
Views: 161

Re: Issues using full speed devices with USB 3.0 hubs

The heading above the section you're reading states that the restriction only applies to products that aren't a Pi 4. The USB3 "hub" is actually a USB2 hub and a USB3 hub connected to the same port. If you plug USB1.1 devices into a USB3 hub, they will appear as children of the USB2 hub. Similarly, ...
by jdb
Sun Aug 02, 2020 11:46 am
Forum: Troubleshooting
Topic: Rpi4 audio glitching problem
Replies: 4
Views: 254

Re: Rpi4 audio glitching problem

Does the noise occur if you run speaker-test? Run speaker-test -c 2 -t sine
by jdb
Fri Jul 31, 2020 11:52 am
Forum: General discussion
Topic: Please improve the sound quality of the Raspberry Pi product.
Replies: 28
Views: 1674

Re: Please improve the sound quality of the Raspberry Pi product.

You cannot expect too much from PWM wave even after passing a low-pass filter. Wrong. Counterexample here: https://en.wikipedia.org/wiki/Super_Audio_CD SACD's data format is a 1-bit digital "PWM" bitstream (actually pulse-density modulation, but the same maths applies in terms of noise shaping). Th...
by jdb
Thu Jul 30, 2020 9:28 am
Forum: General discussion
Topic: RPi4 BCM2711 and ARMv8 Crypto Extensions?
Replies: 61
Views: 7752

Re: RPi4 BCM2711 and ARMv8 Crypto Extensions?

a few other users have found that the gigabit ethernet is heavily crippled by software TLS not being able to keep up but i only see it as being a problem for the small number of people with gigabit internet speeds, anything on lan likely wont have as much crypto on it Recently we enabled NEON durin...
by jdb
Thu Jul 30, 2020 8:12 am
Forum: General discussion
Topic: RPi4 BCM2711 and ARMv8 Crypto Extensions?
Replies: 61
Views: 7752

Re: RPi4 BCM2711 and ARMv8 Crypto Extensions?

john_alan wrote:
Thu Jul 30, 2020 7:56 am
These crypto extensions are essential in this day and age.

If the next Pi doesn't exhibit them, it will fail.
[citation needed]
by jdb
Wed Jul 29, 2020 11:26 am
Forum: General discussion
Topic: Rasperry pi 4 memory geometry information
Replies: 10
Views: 375

Re: Rasperry pi 4 memory geometry information

The LPDDR4 standard has optional support for on-die TRR. This is the part number for the Micron 4GB SDRAM chip: https://www.micron.com/support/tools-and-utilities/fbga?fbga=d9whv#pnlFBGA Registration is required in order to get the datasheet for it. As far as I'm aware, the SDRAM controller does not...
by jdb
Wed Jul 29, 2020 10:51 am
Forum: General discussion
Topic: Rasperry pi 4 memory geometry information
Replies: 10
Views: 375

Re: Rasperry pi 4 memory geometry information

But why do you need this information?
by jdb
Wed Jul 29, 2020 10:46 am
Forum: General discussion
Topic: Rasperry pi 4 memory geometry information
Replies: 10
Views: 375

Re: Rasperry pi 4 memory geometry information

I2Cdetect would report an error if the i2c driver was not loaded. You're getting no results because the Pi does not have a SPD EEPROM.

Why do you want to know what the "memory geometry" is?
by jdb
Tue Jul 28, 2020 3:16 pm
Forum: General discussion
Topic: Raspberry PI 4 and wifi pineapple
Replies: 17
Views: 698

Re: Raspberry PI 4 and wifi pineapple

After finding out what a "wifi pineapple" is, I'm locking this thread. It's a device for doing man-in-the-middle attacks against secured wireless networks.
by jdb
Tue Jul 28, 2020 9:23 am
Forum: General discussion
Topic: Is the 1GbE NIC inside raspberry Pi 4 RSS-capable?
Replies: 6
Views: 381

Re: Is the 1GbE NIC inside raspberry Pi 4 RSS-capable?

RSS support is not required for SMB3. The NIC can handle multiple concurrent TCP connections just fine. At gigabit speeds, there is rarely any drop in throughput even with dozens of active connections. RSS is a performance-enhancing feature in high-end/10GbE controllers where individual CPUs are ass...
by jdb
Tue Jul 28, 2020 9:18 am
Forum: General discussion
Topic: Actual memory bandwidth of raspberry pi4?
Replies: 75
Views: 3687

Re: Actual memory bandwidth of raspberry pi4?

My apologies I was overwhelmed by frustration just now, I have editted the post. But broadcomm seems reluctant to deal with these issues and provide more information about this. Again, I don't think this memory performance for an LPDDR4 memory is satisfying. Jetson utilizes much stronger GPU and it...
by jdb
Tue Jul 28, 2020 7:55 am
Forum: Advanced users
Topic: Is hot plugging a microSD electrically safe?
Replies: 13
Views: 755

Re: Is hot plugging a microSD electrically safe?

The kernel drivers definitely have code that polls an empty SD card slot to determine when a card is inserted, so I expect hot-plug is an expected mode of operation. How well it actually works is a different question, as I spent about an hour yesterday looking for one of those tiny cards I had acci...
by jdb
Tue Jul 28, 2020 7:40 am
Forum: General discussion
Topic: Is the 1GbE NIC inside raspberry Pi 4 RSS-capable?
Replies: 6
Views: 381

Re: Is the 1GbE NIC inside raspberry Pi 4 RSS-capable?

The MAC+driver does not support hashing of incoming packets, which are required for flow queues. pi@raspberrypi:/sys/class/net/eth0 $ sudo ethtool -x eth0 Cannot get RX ring count: Operation not supported pi@raspberrypi:/sys/class/net/eth0 $ sudo ethtool -n eth0 Cannot get RX rings: Operation not su...
by jdb
Sun Jul 26, 2020 3:53 pm
Forum: General discussion
Topic: Does Raspberry PI 4 have problems in 2020?
Replies: 45
Views: 3022

Re: Does Raspberry PI 4 have problems in 2020?

mwrich4 wrote:
Sun Jul 26, 2020 3:45 pm
So much help desk time is wasted with uncertainty when the board rev is not updated religiously.
What does this statement mean?
by jdb
Fri Jul 24, 2020 3:39 pm
Forum: General discussion
Topic: Pi4 Quality Control
Replies: 3
Views: 268

Re: Pi4 Quality Control

Thanks. I'll pass it along.
by jdb
Fri Jul 24, 2020 3:09 pm
Forum: General discussion
Topic: Pi4 Quality Control
Replies: 3
Views: 268

Re: Pi4 Quality Control

Please post a picture of the QR code on the white sticker on the underside of the board.
by jdb
Fri Jul 24, 2020 11:39 am
Forum: Troubleshooting
Topic: STICKY: If you have a Raspberry Pi 4 and are getting bad speeds transferring data to/from USB3.0 SSDs, read this
Replies: 162
Views: 137128

Re: STICKY: If you have a Raspberry Pi 4 and are getting bad speeds transferring data to/from USB3.0 SSDs, read this

The drive's mass storage interface has only one alternate setting, and it's Bulk-Only. It lacks SCSI. There's nothing stopping USB mass-storage from being performant - UAS just manages multiple concurrent IO operations better. If you've been flashing firmware images then it's possible you've install...
by jdb
Fri Jul 24, 2020 10:05 am
Forum: Troubleshooting
Topic: STICKY: If you have a Raspberry Pi 4 and are getting bad speeds transferring data to/from USB3.0 SSDs, read this
Replies: 162
Views: 137128

Re: STICKY: If you have a Raspberry Pi 4 and are getting bad speeds transferring data to/from USB3.0 SSDs, read this

Well, there should be nothing preventing a UAS interface from being used if there is one. Does your mass storage device have UAS capability? Please post the output of sudo lsusb -v.
by jdb
Thu Jul 23, 2020 3:45 pm
Forum: Troubleshooting
Topic: STICKY: If you have a Raspberry Pi 4 and are getting bad speeds transferring data to/from USB3.0 SSDs, read this
Replies: 162
Views: 137128

Re: STICKY: If you have a Raspberry Pi 4 and are getting bad speeds transferring data to/from USB3.0 SSDs, read this

Hang on, I looked up the quirks for that device and it's setting BROKEN_FUA not IGNORE_UAS, which should not result in UAS being blacklisted. Your kernel is still selecting usb-storage for the device for some reason. What's the output of uname -a && lsmod?

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