Post ATPdeJxc0LfvPDkKB6 by jevinskie@mastodon.social
(DIR) More posts by jevinskie@mastodon.social
(DIR) Post #ATPbP3MXEXqTfxznge by GrapheneOS@grapheneos.social
2023-03-08T17:00:11Z
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We've added another PSDS data cache at http://qualcomm.psds.grapheneos.org for devices using Qualcomm GNSS rather than Broadcom GNSS.We plan to use this to implement our PSDS server toggle for Snapdragon Pixels and future Snapdragon devices we'll end up supporting.#grapheneos #privacy #security #gnss #agnss #psds #xtra #qualcomm #broadcom
(DIR) Post #ATPbPpCbMmQ833iXrs by GrapheneOS@grapheneos.social
2023-03-08T17:00:19Z
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Qualcomm uses their own xtra-daemon service instead of the standard AOSP PSDS service like Broadcom. xtra-daemon does support changing the PSDS (XTRA) URLs via gps.conf in the vendor image but we need dynamic configuration. We'll only switch to our server after we integrate this.
(DIR) Post #ATPbuAovYTjbmd7DFo by PomstaZLesa@mastodon.world
2023-03-08T17:05:59Z
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@GrapheneOS future snapdragon devices? afaik, out of the currently supported devices, last snapdragon device will EOL in 2024 August. do you have your eyes on any devices that can utilize it after 2024? is this perhaps for a potential [another attempt at] in-house device design?
(DIR) Post #ATPcAVpJDqwlZA5JzM by Hyolobrika@berserker.town
2023-03-08T17:09:10Z
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@GrapheneOS What exactly is a PSDS data cache, what does it do, and how does it work?
(DIR) Post #ATPcwoUd7kyxMKRb4C by GrapheneOS@grapheneos.social
2023-03-08T17:17:51Z
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@Hyolobrika It's explained at https://grapheneos.org/faq#default-connections. PSDS provides static data about GNSS (GPS, GLONASS, etc.) satellites including their predicted locations at times up to around 7 days in the future. It also provides topographical data, etc. It helps to accelerate obtaining location from GNSS. You only need network access to fetch the data initially when using location and then it works for quite a while offline since it has data that's valid days into the future. It's one form of A-GNSS.
(DIR) Post #ATPd7WC9UojrnIuDS4 by GrapheneOS@grapheneos.social
2023-03-08T17:19:40Z
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@Hyolobrika There's also cellular-based A-GNSS with both control plane and user plane variants. That's documented in the FAQ section below:https://grapheneos.org/faq#other-connectionsGrapheneOS uses our own proxy for user plane (SUPL) cellular A-GNSS by default. We provide a toggle to choose server or disable SUPL. We also disable sending IMSI and phone number to the SUPL server. Other Android devices including nearly every aftermarket OS simply uses supl.google.com directly and sends those identifiers to it.
(DIR) Post #ATPd9i7E99blLPeCem by GrapheneOS@grapheneos.social
2023-03-08T17:20:07Z
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@Hyolobrika There's also cellular-based A-GNSS with both control plane and user plane variants. That's documented in the FAQ section below:https://grapheneos.org/faq#other-connectionsGrapheneOS uses our own proxy for user plane (SUPL) cellular A-GNSS by default. We provide a toggle to choose server or disable SUPL. We also disable sending IMSI and phone number to the SUPL server. Other Android-based devices including nearly every aftermarket OS just use supl.google.com directly and sends those identifiers to it.
(DIR) Post #ATPdB7OxcSUG3bc5sO by GrapheneOS@grapheneos.social
2023-03-08T17:20:14Z
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@Hyolobrika There's also cellular-based A-GNSS with both control plane and user plane variants. That's documented in the FAQ section below:https://grapheneos.org/faq#other-connectionsGrapheneOS uses our own proxy for user plane (SUPL) cellular A-GNSS by default. We provide a toggle to choose server or disable SUPL. We also disable sending IMSI and phone number to the SUPL server. Other Android-based devices including nearly every aftermarket OS just use supl.google.com directly and send those identifiers to it.
(DIR) Post #ATPdJGMcBLfmAZOqpc by GrapheneOS@grapheneos.social
2023-03-08T17:21:47Z
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@PomstaZLesa You're correct that Pixels are no longer using Snapdragon and that the last one using it was the Pixel 5a which will be end-of-life after August 2024 since they had a 3 year support guarantee at launch and it's unlikely the Pixel 5a will get longer support than the minimum guarantee. There's a decent chance that the Pixel 4a (5G) and Pixel 5 will be supported until the Pixel 5a end-of-life but there's no way of knowing until we see what happens at the end of this year.
(DIR) Post #ATPdWhJDJOuFVFDOgC by GrapheneOS@grapheneos.social
2023-03-08T17:24:11Z
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@PomstaZLesa We're still trying to work with OEMs to get a device produced meeting our requirements and that will almost certainly be a Snapdragon device. That's part of our motivation for continuing to make Snapdragon-specific improvements rather than only focusing on Tensor and generic improvements. For example, we made our SUPL proxy compatible with Snapdragon which required extra work and substantial additional testing. One day we may also host our own SUPL server, not just a proxy.
(DIR) Post #ATPdeJxc0LfvPDkKB6 by jevinskie@mastodon.social
2023-03-08T17:25:34Z
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@GrapheneOS is the xtra-daemon a binary blob that requires patching or is the source available?
(DIR) Post #ATPe4Kn5XYfpVgECDQ by GrapheneOS@grapheneos.social
2023-03-08T17:30:16Z
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@jevinskie It's shared source and while we have access to certain revisions of the sources we aren't able to build it for GrapheneOS on Pixels. We don't have to patch it since it supports configuring the services it uses via gps.conf, but as far as we know it can't receive the configuration dynamically from the OS via the HAL so we'll likely need to come up with a way to change the gps.conf that's available to it and then restart it.
(DIR) Post #ATPeiVXyy3hOSBJo0W by Hyolobrika@berserker.town
2023-03-08T17:37:43Z
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@GrapheneOS Thank you. I found your other post about GNSS on GOS just as you posted that but thanks for the explanation anyway.
(DIR) Post #ATPelMYopsXRS24TNw by GrapheneOS@grapheneos.social
2023-03-08T17:38:08Z
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@jevinskie Since we have access to an older revision of the sources, the minor differences from changes they've made since then are easy enough to figure out via the binary. It's a very simple service. It just downloads PSDS databases via HTTPS (or HTTP, if you don't specify the URLs as HTTPS) and obtains time via NTP to determine which data to use rather than using less precise OS time (Android has up to 2s out-of-sync clock, GrapheneOS up to 50ms but only assuming user didn't disable syncing).
(DIR) Post #ATPerAzAmfWbI1AbRY by GrapheneOS@grapheneos.social
2023-03-08T17:39:07Z
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@jevinskie It actually has NTS support which we could enable but we haven't seen any OEM enabling the NTS support and we aren't sure if it's ready for use. It would also be extra attack surface and not particularly useful since this isn't used to set the clock, just to know which data from the GNSS almanac database with predicted satellite locations (main purpose of PSDS) should be used.