[linux-dvb] cx23885 driver and DMA timeouts

stev391 at email.com stev391 at email.com
Thu Jun 26 00:32:07 CEST 2008


 Steve,

I have found the cause of my DMA timeouts, as per your suggestion I
checked the sram settings.
The cause of the issue was in SRAM_CH06 cdt, this was originally set to
0x10480 and is currently set to 0x108d0.  In changeset 7005:a6d2028a4aab
you introduced this as an alternative set of values and then in changeset
7464:20a1412b4f1a it was all converted to these values.  I was wondering
why this value was required to change?

I have not yet had the time to analyse these values in detail, but the
following are possible options that I/we can persue:

1) Set the value back to 0x10480 (diff attached), the following supported
cards will use this value (from a quick glance):
CX23885_BOARD_HAUPPAUGE_HVR1800lp
CX23885_BOARD_HAUPPAUGE_HVR1800
CX23885_BOARD_HAUPPAUGE_HVR1250
CX23885_BOARD_HAUPPAUGE_HVR1500Q
CX23885_BOARD_HAUPPAUGE_HVR1500
CX23885_BOARD_HAUPPAUGE_HVR1200
CX23885_BOARD_HAUPPAUGE_HVR1700
CX23885_BOARD_HAUPPAUGE_HVR1400
CX23885_BOARD_DVICO_FUSIONHDTV_7_DUAL_EXP

2) Introduce another variable in struct cx23885_board to allow board
specific srams.  The sram would not be duplicated in this struct, a
second version would be included in cx23885-core.c (similar to the 7005
changeset except it is now manual configurable and not switching on PCI
id). The down side of this is the cx23885-core.c will be slightly larger,
with a larger memory footprint.

3) Reallocate entire sram, this would require a detailed look on my
behalf to see how much space each variable requires and reallocate it. 
This will potentially break the cards mentioned in option 1 and will take
more time to implement and test. This is highly undesirable my viewpoint.

4) Something else? Please suggest a solution...

Regards,

Stephen

diff -Naur v4l-dvb/linux/drivers/media/video/cx23885/cx23885-core.c
v4l-dvb1/linux/drivers/media/video/cx23885/cx23885-core.c
--- v4l-dvb/linux/drivers/media/video/cx23885/cx23885-core.c   
2008-06-06 14:57:55.000000000 +1000
+++ v4l-dvb1/linux/drivers/media/video/cx23885/cx23885-core.c  
2008-06-26 08:26:42.000000000 +1000
@@ -142,7 +142,7 @@
.name           = "TS2 C",
.cmds_start     = 0x10140,
.ctrl_start     = 0x10680,
-               .cdt            = 0x108d0,
+               .cdt            = 0x10480,
.fifo_start     = 0x6000,
.fifo_size      = 0x1000,
.ptr1_reg       = DMA5_PTR1,

  ----- Original Message -----
  From: "Steven Toth"
  To: stev391 at email.com
  Subject: Re: [linux-dvb] cx23885 driver and DMA timeouts
  Date: Mon, 23 Jun 2008 08:51:10 -0400

  No need to try windows, if you have the driver already running
  (pascoe's patches) then your chipset and hardware are fine.

  Sounds like you have a simple merge issue.

  Try to figure out which parts of the merge actually create the
  problem then bring that issue back to this list for discussion.

  Regards,

  - Steve

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