Em Fri, 26 Jan 2018 17:37:39 -0200
Mauro Carvalho Chehab [off-list ref] escreveu:

Em Fri, 26 Jan 2018 12:17:37 -0200
Mauro Carvalho Chehab [off-list ref] escreveu:

quoted

Hi Alan,

Em Mon, 8 Jan 2018 14:15:35 -0500 (EST)
Alan Stern [off-list ref] escreveu:
  

quoted

On Mon, 8 Jan 2018, Linus Torvalds wrote:
    

quoted

Can somebody tell which softirq it is that dvb/usb cares about?      

I don't know about the DVB part.  The USB part is a little difficult to
analyze, mostly because the bug reports I've seen are mostly from
people running non-vanilla kernels.     

I suspect that the main reason for people not using non-vanilla Kernels
is that, among other bugs, the dwc2 upstream driver has serious troubles
handling ISOCH traffic.

Using Kernel 4.15-rc7 from this git tree:
	https://git.linuxtv.org/mchehab/experimental.git/log/?h=softirq_fixup

(e. g. with the softirq bug partially reverted with Linux patch, and
 the DWC2 deferred probe fixed)

With a PCTV 461e device, with uses em28xx driver + Montage frontend
(with is the same used on dvbsky hardware - except for em28xx).

This device doesn't support bulk for DVB, just ISOCH. The drivers work 
fine on x86.

Using a test signal at the bit rate of 56698,4 Kbits/s, that's what
happens, when capturing less than one second of data:

$ dvbv5-zap -c ~/dvb_channel.conf "tv brasil" -l universal -X 100 -m -t2dvbv5-zap -c ~/dvb_channel.conf "tv brasil" -l universal -X 100 -m -t2
Using LNBf UNIVERSAL
	Universal, Europe
	Freqs     : 10800 to 11800 MHz, LO: 9750 MHz
	Freqs     : 11600 to 12700 MHz, LO: 10600 MHz
using demux 'dvb0.demux0'
reading channels from file '/home/mchehab/dvb_channel.conf'
tuning to 11468000 Hz
       (0x00) Signal= -33.90dBm
Lock   (0x1f) Signal= -33.90dBm C/N= 30.28dB postBER= 2.33x10^-6
dvb_dev_set_bufsize: buffer set to 6160384
  dvb_set_pesfilter to 0x2000
354.08s: Starting capture
354.73s: only read 59220 bytes
354.73s: Stopping capture

[  354.000827] dwc2 3f980000.usb: DWC OTG HCD EP DISABLE: bEndpointAddress=0x84, ep->hcpriv=116f41b2
[  354.000859] dwc2 3f980000.usb: DWC OTG HCD EP RESET: bEndpointAddress=0x84
[  354.010744] dwc2 3f980000.usb: --Host Channel 5 Interrupt: Frame Overrun--
... (hundreds of thousands of Frame Overrun messages)
[  354.660857] dwc2 3f980000.usb: --Host Channel 5 Interrupt: Frame Overrun--
[  354.660935] dwc2 3f980000.usb: DWC OTG HCD URB Dequeue
[  354.660959] dwc2 3f980000.usb: Called usb_hcd_giveback_urb()
[  354.660966] dwc2 3f980000.usb:   urb->status = 0
[  354.660992] dwc2 3f980000.usb: DWC OTG HCD URB Dequeue
[  354.661001] dwc2 3f980000.usb: Called usb_hcd_giveback_urb()
[  354.661008] dwc2 3f980000.usb:   urb->status = 0
[  354.661054] dwc2 3f980000.usb: DWC OTG HCD URB Dequeue
[  354.661065] dwc2 3f980000.usb: Called usb_hcd_giveback_urb()
[  354.661072] dwc2 3f980000.usb:   urb->status = 0
[  354.661107] dwc2 3f980000.usb: DWC OTG HCD URB Dequeue
[  354.661120] dwc2 3f980000.usb: Called usb_hcd_giveback_urb()
[  354.661127] dwc2 3f980000.usb:   urb->status = 0
[  354.661146] dwc2 3f980000.usb: DWC OTG HCD URB Dequeue
[  354.661158] dwc2 3f980000.usb: Called usb_hcd_giveback_urb()
[  354.661165] dwc2 3f980000.usb:   urb->status = 0  

Btw, 

Just in case, I also applied all recent pending dwc2 patches I found at
linux-usb (even trivial unrelated ones) at:

	https://git.linuxtv.org/mchehab/experimental.git/log/?h=dwc2_patches

No differences. ISOCH is still broken.

If anyone wants to see the full logs, it is there:
	https://pastebin.com/XJYyTwPv

Someone pointed me in priv that applying a change at DWC2 BRCM profile to
enable uframe_sched might help.

So, I wrote this patch:
	https://git.linuxtv.org/mchehab/experimental.git/commit/?h=v4.15%2bmedia%2bdwc2&id=19abf0026b7bf1bd44aa9d2add9f958935760ded

And applied on the top of this branch:
	https://git.linuxtv.org/mchehab/experimental.git/log/?h=v4.15%2bmedia%2bdwc2

It is based on Kernel 4.15 vanilla. I applied:
	- all media -next patches that will be sent to Kernel 4.16-rc1;
	- DWC2 patches submitted by Gregor at linux-usb ML;
	- Linus softirq test patch:
		https://git.linuxtv.org/mchehab/experimental.git/commit/?h=v4.15%2bmedia%2bdwc2&id=ccf833fd4a5b99c3d3cf2c09c065670f74a230a7
	- A DT patch that enables VCIQ (needed by some GPU drivers):
		https://git.linuxtv.org/mchehab/experimental.git/commit/?h=v4.15%2bmedia%2bdwc2&id=fd4e9ca6f41d35b6234c30fa29937141e0c09570
	- a few debug patches like this one:
		https://git.linuxtv.org/mchehab/experimental.git/commit/?h=v4.15%2bmedia%2bdwc2&id=f50669c18394f5b5674630e2ebf78a06b023626f
 
I didn't notice any difference. The dwc2 driver is still broken for 
ISOCH transfers:
	https://pastebin.com/nL1Fe9X5

Cheers,
Mauro