The safest solution is to create custom fb_write?
and fb_read? routines.
Maybe James will add these hooks for hardware like
yours.
Then disallow mmap's except probably for the MMIO
regions.
What about adding fb_write / fb_read function in the
framebuffer (device dependant) driver. The same way as
for fb_mmap. I saw that at the beginning of fb_mmap in
fbmem.c, there is a test to see if the device driver
contains its own fb_mmap function, if so the device
driver fb_mmap will be used instead of the "generic"
fb_mmap. What about doing the same thing for fb_write
/ fb_read.
PS: What's your hardware?
Well actually it's a custom chip.
Alain
--- Antonino Daplas [off-list ref] a écrit : > On
Wed, 2002-10-30 at 18:49, alain volmat wrote:
quoted
Hi,
As I said the video card I am now writing a
framebuffer for, doesn't have linear memory, which
means that I can only access a small part of the
memory at a time and then set offset registers in
order to access another part of the memory.
I would like to know if there is such case in
current
quoted
framebuffer drivers ?? If so, what is the common
solution to do that ??
None in the current drivers.
quoted
In fact the problem remains in the case of mmap
(which
quoted
is the most common ;( of course), since the memory
seams to be accessed directly by pointer, there
might
quoted
be no wait to detect if we need to set or not an
offset. In case of fb_read fb_write, it is
possible to
quoted
do that before the actual write at the end (even
if it
quoted
is not sooo beautiful ... ).
The safest solution is to create custom fb_write?
and fb_read? routines.
Maybe James will add these hooks for hardware like
yours.
Then disallow mmap's except probably for the MMIO
regions.
Creating a bank-switching mechanism, besides
entailing a lot of work, is
not entirely safe.
Tony
PS: What's your hardware?
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On Thu, 2002-10-31 at 12:02, alain volmat wrote:
What about adding fb_write / fb_read function in the
framebuffer (device dependant) driver. The same way as
for fb_mmap. I saw that at the beginning of fb_mmap in
fbmem.c, there is a test to see if the device driver
contains its own fb_mmap function, if so the device
driver fb_mmap will be used instead of the "generic"
fb_mmap. What about doing the same thing for fb_write
/ fb_read.
I've seen a post by James sometimes ago about adding fb_write and
fb_read to info->fbops.
Tony
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On Thu, 2002-10-31 at 12:02, alain volmat wrote:
quoted
What about adding fb_write / fb_read function in the
framebuffer (device dependant) driver. The same way as
for fb_mmap. I saw that at the beginning of fb_mmap in
fbmem.c, there is a test to see if the device driver
contains its own fb_mmap function, if so the device
driver fb_mmap will be used instead of the "generic"
fb_mmap. What about doing the same thing for fb_write
/ fb_read.
I've seen a post by James sometimes ago about adding fb_write and
fb_read to info->fbops.
Correct. The next set of fbdev changes will include this plus I added
fb_sync!!! Iknow this will make you happy:-)
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On Fri, 2002-11-01 at 05:44, James Simmons wrote:
quoted
On Thu, 2002-10-31 at 12:02, alain volmat wrote:
quoted
What about adding fb_write / fb_read function in the
framebuffer (device dependant) driver. The same way as
for fb_mmap. I saw that at the beginning of fb_mmap in
fbmem.c, there is a test to see if the device driver
contains its own fb_mmap function, if so the device
driver fb_mmap will be used instead of the "generic"
fb_mmap. What about doing the same thing for fb_write
/ fb_read.
I've seen a post by James sometimes ago about adding fb_write and
fb_read to info->fbops.
Correct. The next set of fbdev changes will include this plus I added
fb_sync!!! Iknow this will make you happy:-)
Indeed :-), not just me, but others too, I guess. Selective hardware
syncs will maximize the graphics instruction pipeline.
Tony
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