Errors loading fbtft on the Intel Edison

[ShawnHymel]

This is a cross-post from https://github.com/notro/fbtft/issues/353, but I figured I would ask here as well to see if you have run into this issue.

I managed to get fbtft compiled with the Edison kernel using the Yocto Project and wallacezq's recipe. I have an Adafruit 1.8" LCD connected to the Edison (SPI bus 5.0). I try to load the module with

modprobe fbtft dma=0
modprobe fbtft_device name=sainsmart18 busnum=5 speed=5000000 bgr=1 gpios=reset:44,dc:45

but dmesg gives me the following:

[   63.099949] fbtft_device:  SPI devices registered:
[   63.099982] fbtft_device:      ads7955 spi5.0 25000kHz 16 bits mode=0x00
[   63.100002] fbtft_device:      spidev spi5.1 25000kHz 8 bits mode=0x00
[   63.100016] fbtft_device:  'fb' Platform devices registered:
[   63.100106] fbtft_device: Deleting spi5.0
[   63.100904] BUG: sleeping function called from invalid context at /media/Project/Yocto/edison-src/out/linux64/build/tmp/work/edison-poky-linux/linux-yocto/3.10.17-r0/linux/mm/slub.c:926
[   63.101049] in_atomic(): 1, irqs_disabled(): 1, pid: 292, name: modprobe
[   63.101118] CPU: 1 PID: 292 Comm: modprobe Tainted: G           O 3.10.17-yocto-standard #5
[   63.101133] Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48
[   63.101147]  f5640590 00000124 f5197cf0 c18ca73a f5197d14 c126d689 c1ac832c 00000001
[   63.101202]  00000001 00000124 f5640890 f5d55284 00000000 f5197d48 c13203d9 f5197d38
[   63.101252]  c18d33bd c18cfab6 c15c7014 00000020 f5d5532c 000080d0 f5197d48 f5d55284
[   63.101303] Call Trace:
[   63.101342]  [<c18ca73a>] dump_stack+0x16/0x18
[   63.101371]  [<c126d689>] __might_sleep+0xe9/0x110
[   63.101401]  [<c13203d9>] kmem_cache_alloc_trace+0x39/0x1a0
[   63.101429]  [<c18d33bd>] ? add_preempt_count+0x7d/0xf0
[   63.101453]  [<c18cfab6>] ? _raw_spin_unlock_irqrestore+0x26/0x60
[   63.101479]  [<c15c7014>] ? setup+0x5d4/0x840
[   63.101504]  [<c15c7014>] setup+0x5d4/0x840
[   63.101530]  [<c1270ddb>] ? get_parent_ip+0xb/0x40
[   63.101555]  [<c18d34c5>] ? sub_preempt_count+0x95/0xf0
[   63.101581]  [<c15c00fa>] spi_setup+0x4a/0x120
[   63.101609]  [<c1586650>] ? klist_devices_get+0x20/0x20
[   63.101634]  [<c1586507>] ? bus_find_device+0x67/0x90
[   63.101660]  [<c15c0301>] spi_add_device+0xe1/0x1d0
[   63.101688]  [<c15c0eff>] spi_new_device+0x7f/0xc0
[   63.101725]  [<f842c492>] fbtft_device_init+0x492/0x1000 [fbtft_device]
[   63.101754]  [<c1319cac>] ? __vunmap+0x7c/0xf0
[   63.101780]  [<f842c000>] ? 0xf842bfff
[   63.101805]  [<c120017a>] do_one_initcall+0xaa/0x170
[   63.101828]  [<c120017a>] ? do_one_initcall+0xaa/0x170
[   63.101856]  [<c18c8967>] ? set_section_ro_nx+0x54/0x59
[   63.101885]  [<c129e443>] load_module+0x1113/0x16c0
[   63.101912]  [<c132b015>] ? kernel_read+0x35/0x50
[   63.101948]  [<c129eb6d>] SyS_finit_module+0x7d/0xc0
[   63.101975]  [<c130661b>] ? vm_mmap_pgoff+0x7b/0xa0
[   63.102007]  [<c18d0178>] syscall_call+0x7/0xb
[   63.102034] spi spi5.0: setting default chip values
[   63.102081] ------------[ cut here ]------------
[   63.102108] WARNING: at /media/Project/Yocto/edison-src/out/linux64/build/tmp/work/edison-poky-linux/linux-yocto/3.10.17-r0/linux/kernel/softirq.c:160 local_bh_enable_ip+0x98/0xe0()
[   63.102120] Modules linked in: fbtft_device(O+) fbtft(O) fb_sys_fops syscopyarea sysfillrect sysimgblt usb_f_acm u_serial g_multi libcomposite bcm_bt_lpm bcm4334x(O)
[   63.102208] CPU: 1 PID: 292 Comm: modprobe Tainted: G           O 3.10.17-yocto-standard #5
[   63.102222] Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48
[   63.102234]  c1ac6794 00000000 f5197c68 c18ca73a f5197c90 c12408be c1acfc6b c1ac6794
[   63.102285]  000000a0 c1248c98 c1248c98 c1522eb1 00000000 f6c4b024 f5197ca0 c1240982
[   63.102334]  00000009 00000000 f5197cac c1248c98 f6c4b0a4 f5197cb4 c18cfa7f f5197cf0
[   63.102384] Call Trace:
[   63.102413]  [<c18ca73a>] dump_stack+0x16/0x18
[   63.102442]  [<c12408be>] warn_slowpath_common+0x5e/0x80
[   63.102467]  [<c1248c98>] ? local_bh_enable_ip+0x98/0xe0
[   63.102491]  [<c1248c98>] ? local_bh_enable_ip+0x98/0xe0
[   63.102519]  [<c1522eb1>] ? intel_mid_dma_alloc_chan_resources+0x71/0x1a0
[   63.102545]  [<c1240982>] warn_slowpath_null+0x22/0x30
[   63.102570]  [<c1248c98>] local_bh_enable_ip+0x98/0xe0
[   63.102594]  [<c18cfa7f>] _raw_spin_unlock_bh+0x1f/0x30
[   63.102620]  [<c1522eb1>] intel_mid_dma_alloc_chan_resources+0x71/0x1a0
[   63.102645]  [<c18bb39a>] ? klist_put+0x3a/0x90
[   63.102672]  [<c152075b>] dma_chan_get+0x3b/0xc0
[   63.102697]  [<c15215c5>] __dma_request_channel+0x195/0x370
[   63.102722]  [<c1501668>] ? pci_get_subsys+0x38/0x40
[   63.102745]  [<c15c5aa0>] ? u32_reader+0x60/0x60
[   63.102770]  [<c15c6ec9>] setup+0x489/0x840
[   63.102796]  [<c1270ddb>] ? get_parent_ip+0xb/0x40
[   63.102822]  [<c18d34c5>] ? sub_preempt_count+0x95/0xf0
[   63.102849]  [<c15c00fa>] spi_setup+0x4a/0x120
[   63.102876]  [<c1586650>] ? klist_devices_get+0x20/0x20
[   63.102901]  [<c1586507>] ? bus_find_device+0x67/0x90
[   63.102927]  [<c15c0301>] spi_add_device+0xe1/0x1d0
[   63.102954]  [<c15c0eff>] spi_new_device+0x7f/0xc0
[   63.102990]  [<f842c492>] fbtft_device_init+0x492/0x1000 [fbtft_device]
[   63.103018]  [<c1319cac>] ? __vunmap+0x7c/0xf0
[   63.103042]  [<f842c000>] ? 0xf842bfff
[   63.103066]  [<c120017a>] do_one_initcall+0xaa/0x170
[   63.103089]  [<c120017a>] ? do_one_initcall+0xaa/0x170
[   63.103117]  [<c18c8967>] ? set_section_ro_nx+0x54/0x59
[   63.103145]  [<c129e443>] load_module+0x1113/0x16c0
[   63.103170]  [<c132b015>] ? kernel_read+0x35/0x50
[   63.103205]  [<c129eb6d>] SyS_finit_module+0x7d/0xc0
[   63.103232]  [<c130661b>] ? vm_mmap_pgoff+0x7b/0xa0
[   63.103264]  [<c18d0178>] syscall_call+0x7/0xb
[   63.103282] ---[ end trace b72fd31158b70fba ]---
[   63.127052] fbtft_device:  GPIOS used by 'sainsmart18':
[   63.127075] fbtft_device:    'reset' = GPIO44
[   63.127090] fbtft_device:    'dc' = GPIO45
[   63.127102] fbtft_device:  SPI devices registered:
[   63.127121] fbtft_device:      spidev spi5.1 25000kHz 8 bits mode=0x00
[   63.127138] fbtft_device:      fb_st7735r spi5.0 5000kHz 8 bits mode=0x00
[   63.265662] intel_mid_ssp_spi_unified 0000:00:07.1: ERROR : DMA buffers already mapped

I do not get a /dev/fb? device, so it seems the module is running into an issue with DMA buffers. As far as I can tell, between the recipe's patches and dma=0, I should be disabling DMA on fbtft, but it does not seem to be the case. I do not want DMA because as far as I know, the Edison does not have DMA on SPI.

How do I prevent fbtft from using DMA? Any help would be appreciated!

[victorconka]

Hi ShawnHymel, I'm having a similar issue. I have dma disabled in the fbtft controller and stopped getting the : ERROR : DMA buffers already mapped. My error is related to slub.c file. [ 69.954789] BUG: sleeping function called from invalid context at /home/usuario/edison/workspace/linux-kernel/mm/slub.c:928 [ 69.954899] in_atomic(): 1, irqs_disabled(): 1, pid: 293, name: modprobe root@edison:~# [ 70.251017] fb_ili9341 spi5.0: fbtft_update_display: write_vmem failed to update display buffer [ 70.336753] fb_ili9341 spi5.0: fbtft_update_display: write_vmem failed to update display buffer Actually I do get fb0, but if I try to cat /dev/urandom > /dev/fv0 I get the error cat: write error: No space left on device

Did you get to solve your problem ? Regards, Viktor

[ShawnHymel]

@vsobolyev I never did solve the issue, but I've head that the new kernel on the latest Yocto build for Edison fixed the DMA issues. Haven't tried them yet, though.

[victorconka]

Thanx for the reply @ShawnHymel. What a bummer. I'll have another try with the @presslab-us version of fbtft. Next thing is to give a try to the newer versions of kernel. I was thinking of 4.1-rc.