Hello, everyone
I'm using kernel version 2.2.13 on my MPC823 FADS board
to display on TV. I have a problem:
After the system boot up, the text on the TV flicker fiercely out,
if I disable the I-Cache throught the EST visionProbe tool,
TV will not flicker out again.
Of course, if I disable the cache when the system boot up,
TV display OK.
So there is some relation between the cache and the video, I guess.
Do you have any suggestion?
Thanks in advacned!
BRs,
Shuangjun
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
We experimented at Apple with cacheable frame buffers and this is what we saw.
I believe this is caused by the cache being on for the region of memory used
for the frame buffer. You'll see little 16 byte chunks of memory sparkling as
the cache finally dumps out dirty cache lines into the real frame buffer.
You can fix this by mapping the area of the frame buffer with cache disabled,
or you can add code to some periodic timer handler to do a DCBF on the region
of the frame buffer each time the timer ticks (this is not cheap, however).
a
On
Wed, 26 Jan 2000, Shuangjun Zhu wrote: > Hello, everyone
I'm using kernel version 2.2.13 on my MPC823 FADS board
to display on TV. I have a problem:
After the system boot up, the text on the TV flicker fiercely out,
if I disable the I-Cache throught the EST visionProbe tool,
TV will not flicker out again.
Of course, if I disable the cache when the system boot up,
TV display OK.
So there is some relation between the cache and the video, I guess.
Do you have any suggestion?
Thanks in advacned!
BRs,
Shuangjun
--
Alan Mimms Packet Engines, Inc. Spokane, Washington [99214-0497]
USA, Earth, Sol, Milky Way, The Local Group, Virgo Supercluster, U0
Despite the cost of living, have you noticed how popular it remains?
-- Steven Wright?
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
Forgot this: One more possibility is to make the frame buffer region of address
space cacheable but write-thru rather than copy-back.
a
On Wed, 26 Jan 2000, Alan Mimms wrote: > We experimented at Apple with
cacheable frame buffers and this is what we saw. >
I believe this is caused by the cache being on for the region of memory used
for the frame buffer. You'll see little 16 byte chunks of memory sparkling as
the cache finally dumps out dirty cache lines into the real frame buffer.
You can fix this by mapping the area of the frame buffer with cache disabled,
or you can add code to some periodic timer handler to do a DCBF on the region
of the frame buffer each time the timer ticks (this is not cheap, however).
a
On
Wed, 26 Jan 2000, Shuangjun Zhu wrote: > Hello, everyone
quoted
I'm using kernel version 2.2.13 on my MPC823 FADS board
to display on TV. I have a problem:
After the system boot up, the text on the TV flicker fiercely out,
if I disable the I-Cache throught the EST visionProbe tool,
TV will not flicker out again.
Of course, if I disable the cache when the system boot up,
TV display OK.
So there is some relation between the cache and the video, I guess.
Do you have any suggestion?
Thanks in advacned!
BRs,
Shuangjun
--
Alan Mimms Packet Engines, Inc. Spokane, Washington [99214-0497]
USA, Earth, Sol, Milky Way, The Local Group, Virgo Supercluster, U0
Despite the cost of living, have you noticed how popular it remains?
-- Steven Wright?
--
Alan Mimms Packet Engines, Inc. Spokane, Washington [99214-0497]
USA, Earth, Sol, Milky Way, The Local Group, Virgo Supercluster, U0
Despite the cost of living, have you noticed how popular it remains?
-- Steven Wright?
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
Shuangjun Zhu wrote:
After the system boot up, the text on the TV flicker fiercely out,
if I disable the I-Cache throught the EST visionProbe tool,
Determine your silicon revision and look on the Motorola web
site for errata and application notes. Early versions of the
823 didn't work so well, especially at high resolution and
refresh rates. Later versions of the 823 added somewhat
undocumented SIU configurations to improve the arbitration of
the U-bus and access to the frame buffer by the video controller.
If all seems well on the silicon front, make sure your video
configuration is proper. Excessively high (and unnecessary)
refresh rates cause problems.
-- Dan
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/