From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Date: Tue, 20 Jan 2015 14:16:35 +0100 Subject: [U-Boot] [linux-sunxi] [u-boot 2/2] sun5i: bump DEBE priority (useful on a10s only) In-Reply-To: <20150120101630.0ac3616e@i7> References: <4250c53f8df139084acfaad14a88819a600b9965.1420399561.git.hramrach@gmail.com> <54A99952.6080905@redhat.com> <20150119062947.3dac60c3@i7> <20150120101630.0ac3616e@i7> Message-ID: <54BE5533.4070402@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi, On 20-01-15 09:16, Siarhei Siamashka wrote: > On Mon, 19 Jan 2015 06:29:47 +0200 > Siarhei Siamashka wrote: > >> On Sun, 04 Jan 2015 20:49:38 +0100 >> Hans de Goede wrote: >> >>> Hi, >>> >>> On 04-01-15 20:19, Michal Suchanek wrote: >>>> Setting magic 'reserved' hpcr bit on sun5i DEBE seems required for >>>> smooth HDMI scanout of large frambuffer (eg. 1080p). >>>> >>>> This fix comes at the cost of some overall memory bandwidth so it >>>> might be appropriate to detect a10s and only apply there (and not a13). >>> >>> Hmm, Sairhei is the expert on this, adding him to the Cc. Sairhei, what >>> do you think of the proposed change ? >> >> I don't have A10s hardware, so have no idea and can't test anything >> myself. >> >> It would be great to have a better description of what exactly is >> happening before the patch. And precisely how the patch is helping. >> A description of the test setup and benchmark numbers would be >> appreciated. And it would be perfect if somebody else could reproduce >> the test and confirm the results. >> >> I may try to check A20 with the bus width artificially reduced >> to 16 bits (not a totally unrealistic configuration, since >> A20-OLinuXino-LIME board exists). If sun5i and sun7i are similar >> enough, then the magic reserved bit may have some effect there too. >> But that's a different hardware either way. > > Done these tests with A20. Ironically, now the tables have turned and > A10 seems to be doing a better job than A20 at low DRAM clock speeds > (~408MHz) and 16-bit bus width when dealing with full-hd monitors. > > Just like Michal observed on A10s, setting 0x5031 as DEFE host port > config makes things much worse on A20. Overall, the test results look > in the following way on A20 with 16-bit DRAM clocked at 408MHz (yes, > none of the real boards uses such a slow DRAM setup) while running > lima-memtester and driving 1920x1080-32 at 60Hz monitor: > > 0x1035 - The screen regularly blanks, but comes back again instantly. > 0x1037 - The screen regularly blanks, but comes back again instantly. > 0x5031 - Severe screen shaking. > > Unlike A10, there does not seem to be any difference between using DEBE > or DEFE for framebuffer scanout on A20, so using DEBE has the same > effect as listed above. Setting the magic 'reserved' hpcr bit 1 > (0x1037 value) does not seem to have any effect on sun7i. It is > great that it is apparently helping on sun5i/A10s though. Thanks for running these tests, this makes me more confident that I only need to enable DEFE in u-boot on A10, and can directly use DEBE on the others. Regards, Hans