Messages in this thread | | | Date | Fri, 18 Feb 2022 11:45:31 -0600 | Subject | Re: [PATCH RFC] staging: r8188eu: comment about the chip's packet format | From | Larry Finger <> |
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On 2/18/22 04:22, Dan Carpenter wrote: > On Fri, Feb 18, 2022 at 10:22:53AM +0100, Martin Kaiser wrote: >> The structs phy_rx_agc_info and phy_status_rpt define parts of the >> header data that the r8188eu chipset sends to this driver via usb. >> >> Add a comment to clarify that we cannot modify the content of these >> structures and remove seemingly unused fields. >> >> Signed-off-by: Martin Kaiser <martin@kaiser.cx> >> --- >> >> Dear all, >> >> I experimented with "cleaning up" these structures and related code before >> discovering that their content comes from usb packets we receive from the >> r8188eu chipset. >> >> Would it make sense to add a word of warning to prevent others from >> repeating this exercise? > > Just the fact that these structs are endian means they're from the > firmware or the network. > > If a struct has a pointer in it, then it's rarely part of the UAPI but > if it has endian data then it probably is.
Additionally, do not change any struct with the __packed attribute. Most will have endian variables as well, but not all will.
Testing after modifying any struct is a necessity.
Larry
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