On 8/6/20 2:36 PM, Wolfgang Grandegger wrote: > Am 06.08.20 um 13:04 schrieb Marek Vasut: >> On 8/6/20 12:53 PM, Wolfgang Grandegger wrote: >>> This reverts commit c5f4b805755912a3d2fe20f014b6b6ab0473bd73. >>> >>> Conflicts: >>> arch/arm/mach-socfpga/misc_gen5.c >>> >>> Without socfpga_sdram_apply_static_cfg(), the system hangs when Linux >>> calls altvipfb2_start_hw() of the Intel Video and Image Processing(VIP) >>> Frame Buffer II driver (drivers/video/fbdev/altvipfb2.c) >> >> There is no such driver in mainline U-Boot or Linux. > > It's a simple frame buffer driver from linux-socfpga for the IP core > Intel Video and Image Processing(VIP) Frame Buffer II. It actually > hangs here when the streaming starts: > > https://github.com/altera-opensource/linux-socfpga/blob/socfpga-5.4.44-lts/drivers/video/fbdev/altvipfb2.c#L69 > > I can also hang the system if I setup and start the FB with just a > few U-Boot commands. I think the system hangs when the IP core starts > reading the FB data from the system memory.
I am CCing Dinh , I recall there was some discussion about hangs on CycloneV and it was fixed recently. >>> , but only >>> after a power cycle (cold boot). The issue does not show up after a >>> soft reset (warm boot) and with v2018.11. >> >> See the commit message of the patch this is reverting, I believe there >> is a deeper issue with the static config register. Can you investigate? > > I read the commit message, but well, I can't follow all the details :(. > On the other hand, it seems also not clear why the fix was added. Any > idea what to investigate. The system was repeatedly rebooted in a loop, the FPGA was loaded before Linux booted. After hundreds of reboots, the system got stuck on setting up the static cfg register. I think there was even another email exchange where the suggestion was to make this apply_static_cfg optional and only use it when the DRAM port is enabled in the quartus design. Maybe that is the way out of this ?