Can CPU write video memory directly?
Hi all,
Now I am debugging video chip MB86297A.Reference to hardware manual,I
have configured PCI registers ,Carmine Control registers and DRAM Control registers under U-boot , other modules registers have not been configured.I dont know how to verify DRAM is configured correctly. When I "md" video memory,they are all zero,and after I "mm" video memory,they are "md" still display all zero .Are DRAM Control registers configured wrong? Does CPU modify video memory?
Thanks!
Signature · 2 lines
View this message in context: http://www.nabble.com/Can-CPU-write-video-memory-directly--tp17340898p17340898.html Sent from the Uboot - Users mailing list archive at Nabble.com.
Hi Zhanglei459,
Quoted 6 lines
Now I am debugging video chip MB86297A.Reference to hardware manual,I
have configured PCI registers ,Carmine Control registers and DRAM Control registers under U-boot , other modules registers have not been configured.I dont know how to verify DRAM is configured correctly. When I "md" video memory,they are all zero,and after I "mm" video memory,they are "md" still display all zero .
Something must be wrong in your configuration. I recently did a standard "mtest" on a CoralP attached graphics memory *after* correctly setting up the CoralP control registers. Note that I had to setup CCF and MMR registers correctly (swapping endinanness by hand!).
Quoted 1 line
Are DRAM Control registers configured wrong?
Most likely.
Quoted 1 line
Does CPU modify video memory?
No, why should it?
Cheers
Detlev
Signature · 5 lines
five monkeys, two typewriters, ten minutes -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de