Hi, On 03/20/2014 11:50 PM, Ratin wrote: > On Friday, October 18, 2013 10:25:27 AM UTC-7, Siarhei Siamashka wrote: >> http://irclog.whitequark.org/linux-sunxi/2013-07-29#4520613; >> >> >> >> 10:10 <Tsvetan> the reason we made 384Mhz image is, because when we had >> enough >> >> boards produced >> >> 10:10 <Tsvetan> we noticed that 20% of A20 boards fail on clock more than >> 400Mhz >> >> 10:11 <Tsvetan> replacing the A20 chips on them make them alive >> >> 10:11 <Tsvetan> which made us think that A20 chips have some tolerances and >> >> not all can run above 400Mhz >> >> 10:11 <wingrime> Tsvetan: хи >> >> 10:11 <Tsvetan> I ask Tom and he observed the same >> >> 10:11 <Tsvetan> so we decided to generate images with 384 to be on the >> >> safe side to all boards >> >> 10:12 <Tsvetan> 80% of the boards still can run up to 480Mhz >> >> 10:12 <Tsvetan> btw datasheet say nothing for max safe frequency >> >> 10:12 <Tsvetan> we found this in fiel >> >> 10:12 <wingrime> Tsvetan: we still not have any auto testing framework >> >> 10:12 <Tsvetan> field >> >> 10:12 <oliv3r> wingrime: you mean for dram timings? >> >> 10:13 <wingrime> oliv3r: yex, some mistery >> >> 10:13 <Tsvetan> so running at 400-432-480 may work >> >> 10:13 <oliv3r> i guess it's with overlcocking a PC, you get it with a safe >> >> setting, and then overclock it to whatever works for you >> >> 10:13 <Tsvetan> but you do not know what tolerances your chips have >> >> 10:13 <Tsvetan> and when it will fail infield >> >> 10:13 <wingrime> Tsvetan: are you using same dram ic ? >> >> 10:13 <oliv3r> Tsvetan: so cubieboard2 also runs at 384 MHz by default now? >> >> 10:13 <Tsvetan> same memory chips >> >> 10:13 <Tsvetan> BTW A10 chips do not suffer this problem >> >> 10:14 <Tsvetan> and work fine on same layout up to 480Mhz >> >> 10:14 <Tsvetan> so its up to you at what memory clock you want to run your >> board >> >> 10:14 <Tsvetan> our statistic though says to stay at 384 to be on the safe >> side >> >> 10:15 <oliv3r> better safe then sorry ;) >> >> >> >> The 480MHz dram clock frequency has been also confirmed to cause problems >> >> for at least one user at www.cubieforums.com when running Qt5. >> >> >> >> Signed-off-by: Siarhei Siamashka <[email protected]> >> >> --- >> >> board/sunxi/dram_cubieboard2.c | 2 +- >> >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> >> >> diff --git a/board/sunxi/dram_cubieboard2.c b/board/sunxi/dram_cubieboard2.c >> >> index 370a3d9..287673c 100644 >> >> --- a/board/sunxi/dram_cubieboard2.c >> >> +++ b/board/sunxi/dram_cubieboard2.c >> >> @@ -4,7 +4,7 @@ >> >> #include <asm/arch/dram.h> >> >> >> >> static struct dram_para dram_para = { >> >> - .clock = 480, >> >> + .clock = 384, >> >> .type = 3, >> >> .rank_num = 1, >> >> .density = 4096, >> >> -- >> >> 1.8.1.5
Hmm, it seems this patch never got merged into the u-boot-sunxi git repo, are there any objections to me merging this during one of the coming days ? Regards, Hans -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
