I have been noticing a bug on CM7 for quite some time now. It's a known bug, that affects many devices (actually, I *believe* it affects them all), and that me and Tom_G have discussed recently. I created this topic for the purpose of having a place where people can actively discuss the issue and gather all the relevant info. While I could discuss it in the official CM7 topic, it'd get lost between all the other messages.
First of all, some brief notions of how MMS work: MMSs are data sent over your carrier. This means that you need Data Enabled in order to send a MMS. You can activate Data on Settings, although it comes enabled by default on CM7 (Settings -> Wireless & Networks -> Mobile Network). Without Data Enabled, your MMS will fail to send, and you will not be able to receive MMSs either.
In order to send a MMS, you also need a MMS APN. There are two main types of APN that concern the topic: MMS and Internet APN. Both are related to the usage of Data by the network, and the network knows how to differentiate "MMS Data" from "Internet Data" . However, they are independent, and you are not required to use "Internet Data" in order to use the MMS APN.
The problem with CM is exactly that: for some reason, on CM7 you *need* a functional Internet APN in order to send a MMS. That is not how it is supposed to work, nor it is how it works on other ROMs (for example, GSF). For those with a Data plan, this is a minor bug. But for those without one, this means I have to pay for a day of Internet Data (1.29€) everyday I want to send/receive a MMS. If CM7 allowed me to send/receive solely based on the MMS APN (like it is supposed to), no Data would be charged (my phone plan includes unlimited MMSs to everyone on my carrier).
2G/3G does not interfere with the process itself; having 3G enabled simply makes sending/receiving data faster. You can still receive MMSs on 2G.
That being cleared out, let us see how you can test if you have the issue or not:
- Step 1: Make sure your MMS APN is well configured. (Settings -> Wireless & Networks -> Mobile Networks -> Access Point Names).
- Step 2: Delete your Internet APN, or click on it and change its "APN" field (I changed mine from net2.vodafone.pt to 123net2.vodafone.pt; whenever I want it working again I'll just go there and take the 123 out).
- Step 3: Try to send a MMS without the functioning Internet APN.
- Step 4 (optional): Try sending a MMS with the Internet APN correctly configured.
- Step 5: Report your results.
I am currently away from home but will be posting logcats of this issue soon. MMSs work as they should on GSF (they work without an Internet APN), if someone wants a comparison. I tried pushing MMS.apk app to CM7, but it didn't solve the issue: Tom_G suspects it is in the framework. Perhaps it'd help if Wbaw told us which apps he copied from CM7 to his ROM (and therefore, which apps do not appear to be responsible for the issue).
Thanks for your time!