Hi, On Tue, Apr 17, 2018 at 09:49:22PM -0400, Devin Heitmueller wrote: > [ 68.750809] cx88[0]: video y / packed - dma channel status dump > [ 68.750811] cx88[0]: cmds: initial risc: 0x8aa98000 > [ 68.750813] cx88[0]: cmds: cdt base : 0x00180440 > [ 68.750815] cx88[0]: cmds: cdt size : 0x0000000c > [ 68.750816] cx88[0]: cmds: iq base : 0x00180400 [...] > [ 68.750887] cx88[0]: vbi - dma channel status dump [...] > [ 68.750899] cx88[0]: cmds: iq wr ptr : 0x0000017f > [ 68.750901] cx88[0]: cmds: iq rd ptr : 0x00000011 > [ 68.750902] cx88[0]: cmds: cdt current : 0x00000638 [...] > [ 68.750910] cx88[0]: risc0: 0x8aa98000 [ sync sol irq2 23 21 19 cnt0 resync count=0 ] > [ 68.750913] cx88[0]: risc1: 0x00180440 [ INVALID 20 19 count=1088 ] > [ 68.750915] cx88[0]: risc2: 0x0000000c [ INVALID count=12 ] > [ 68.750918] cx88[0]: risc3: 0x00180400 [ INVALID 20 19 count=1024 ] The VBI instruction queue read pointer points outside the VBI instruction queue and into the video y/packed CMDS (to 0x180000+0x11*4). The values next to the iq rd ptr look ok. We only initialize the iq rd ptr to zero in cx88_sram_channel_setup and then never touch it again. The hardware takes care of updating it. Maybe cx88_sram_channel_setup is sometimes called for channel 24 while the VBI risc engine is still running? One could try adding a WARN_ONCE at the top of the function to catch that case. Best regards, Daniel
