Messages in this thread | | | Date | Mon, 10 Jul 2006 23:18:45 +0800 | From | "Antonino A. Daplas" <> | Subject | Re: [PATCH v2] cirrus-logic-framebuffer-i2c-support.patch |
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Krzysztof Halasa wrote: > "Antonino A. Daplas" <adaplas@pol.net> writes: > >> Eventually, I'm the one who's going to maintain the code, most >> of the drivers in the video directory are practically abandoned. > > BTW, it's fortunate that you are maintaing it. The I2C code in cirrusfb > uses vga_wseq() and vga_rseq(). Is it safe WRT races between I2C > adapter code and fb code? I don't see any locking here, and both > functions are non-atomic (write merging and posting will not break it, > but it looks like I need a lock for concurent access).
Correcting myself: vga_wseq() is not a problem in little endian machines because the 2 single-byte writes are done with a single 2-byte write. vga_rseq() is not safe though.
I don't know how big a problem this is, reading the i2c bus while the video mode is changing..., but I agree that it might be worthwhile to at least lock sequencer access.
Tony
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