Re: [Dri-devel] Using drm (fwd)
Well, it is late Saturday here. I know everyone is busy, but can at least someone confirm that they know the answer but just don't have time for it ? I'd hate to lose a weekend waiting for something that's not going to come.. Vladimir Dergachev -- Forwarded message -- Date: Wed, 10 Oct 2001 18:08:50 -0400 (EDT) From: [EMAIL PROTECTED] To: Keith Whitwell [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: [Dri-devel] Using drm (fwd) On Wed, 10 Oct 2001, Keith Whitwell wrote: On Wed, 10 Oct 2001 15:45, [EMAIL PROTECTED] wrote: On Wed, 10 Oct 2001, Daryll Strauss wrote: On Wed, Oct 10, 2001 at 05:13:40PM -0400, [EMAIL PROTECTED] wrote: So, can anyone answer any of the questions below, or do I have to write drm for multimedia ? The DRM is an architecture for accessing hardware directly. What functions are implemented in any given kernel module is driven by the requirements of the applications running on top of it. That's typically OpenGL at that point. Daryll, did you read the questions ? I am asking specific things about drm interface. Like what drm handles mean, for example. So, most of the drivers are not going to have a function call to support your arbitrary DMA. I am not interested in most drivers. Heck, I am not even looking for that function. I want to know what can I do with the buffer I allocated using drm. Now, I aprreciate your desire to provide some advice, but I am not interested in general considerations of writing a DMA driver. I want to know answers to specific questions, like What AGP Offset is used for ? it is not specific to any card, it is not specific to what I am trying to do. Can anyone answer it ? First, your best bet is to read and understand the 3d driver associated with whatever hardware you're looking at. Most of the questions you are asking can be most easily answered by examination of the code. That's what I am trying to do. With not much luck so far. The reason (at least to me) is that the 3d driver is the interaction of 3 parts: kernel drm module, XFree driver (like radeon_dri.c) and the dri part (whatever goes into radeon_dri.so). Second, it is easiest to answer your questions if you refer to specific lines in specific files. There is no variable called AGP Offset anywhere in the drm. Maybe there are some with similar names, but I can't tell which one you're talking about. Finally, someone who knows the stuff :)) No, there is no such variable, but this phrase I plucked from the comment. Here is an example from radeon.h: /* CP vertex/indirect buffer data */ unsigned long bufStart;/* Offset into AGP space */ drmHandle bufHandle; /* Handle from drmAddMap */ drmSize bufMapSize; /* Size of map */ int bufSize; /* Size of buffers (in MB) */ unsigned char *buf;/* Map */ int bufNumBufs; /* Number of buffers */ drmBufMapPtr buffers; /* Buffer map */ Now, from these I guess that *buf is where I can access the data directly for Xserver. bufSize is the size of the thing - does it have to be in MB ? Or just page-aligned is fine ? bufStart - what do I use this for ? Can I use it to reference data in the buffer or do I have to add or subtract a magic number from it before writing into card's registers ? (and to answer your questions: I have made a copy of the same fields /with buf replaced with capture and allocated space.. nothing seems to crash.., 3d workds, 1mb is reserved someplace. /) Thirdly, nobody's got the time or patience to explain the entire workings of the drm to you. Make an honest attempt to read and understand the code. Ask a few questions and you'll get a few answers. Ask a thousand questions and you will be lucky to get any at all. Ok, I'll leave the other questions for later. Vladimir Dergachev Keith _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com ___ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel ___ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
Re: [Dri-devel] Using drm (fwd)
-- Forwarded Message -- Subject: Re: [Dri-devel] Using drm (fwd) Date: Sat, 13 Oct 2001 16:42:59 -0600 From: Keith Whitwell [EMAIL PROTECTED] To: [EMAIL PROTECTED] That's what I am trying to do. With not much luck so far. The reason (at least to me) is that the 3d driver is the interaction of 3 parts: kernel drm module, XFree driver (like radeon_dri.c) and the dri part (whatever goes into radeon_dri.so). Second, it is easiest to answer your questions if you refer to specific lines in specific files. There is no variable called AGP Offset anywhere in the drm. Maybe there are some with similar names, but I can't tell which one you're talking about. Finally, someone who knows the stuff :)) No, there is no such variable, but this phrase I plucked from the comment. Here is an example from radeon.h: /* CP vertex/indirect buffer data */ unsigned long bufStart;/* Offset into AGP space */ drmHandle bufHandle; /* Handle from drmAddMap */ drmSize bufMapSize; /* Size of map */ int bufSize; /* Size of buffers (in MB) */ unsigned char *buf;/* Map */ int bufNumBufs; /* Number of buffers */ drmBufMapPtr buffers; /* Buffer map */ Now, from these I guess that *buf is where I can access the data directly for Xserver. bufSize is the size of the thing - does it have to be in MB ? It is interpreted as mb, hence the comment. Or just page-aligned is fine ? bufStart - what do I use this for ? Can I use it to reference data in the buffer or do I have to add or subtract a magic number from it before writing into card's registers ? This is an offset from the start of the agp apperture. These fields are setup in the 2d driver to tell the 3d driver how memory is layed out. Have a look at radeon_dri.c to see how agp space is partitioned up and these values are calculated. (and to answer your questions: I have made a copy of the same fields /with buf replaced with capture and allocated space.. nothing seems to crash.., 3d workds, 1mb is reserved someplace. /) I don't think that copying these fields is going to reserve you any memory. You'll need to modify radeon_dri.c to actually reserve memory. If you add a field called 'KeithIsAMillionaire', it doesn't automatically make me rich... Keith --- _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com ___ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
Re: [Dri-devel] Using drm (fwd)
So, can anyone answer any of the questions below, or do I have to write drm for multimedia ? thanks Vladimir Dergachev interface of doing captures. I'm currently working on a new Xv function (XvShmGetImage) that will do this, and also when I see some code from your I am asking about a different problem - not how to get the data from X to the client, but how to ask drm nicely to make a DMA transfer. I suspect (!) that I can simply write the correct values into the registers and the DMA will happen, but I am not clear about the semantics. For example, is AGP Offset the address from the point of view of video card or something else ? Do I have to subtract framebuffer address from it ? What is the significance of card specific drm structures ? Why do we need them ? Why have a separate area for textures ? Can I modify it dynamically ? (so as not to reserve 1mb chunk of ram for capture buffer). What drm handles are for and whether there is a small test app that exercises drm interface from command line (i.e. not inside Xserver or glx client). What do I do about IRQ support ? there seems to be no mention of it in drm structures, but there are a number of IRQs that could occur (vsync, hsync, DMA completion (several different sources, i.e. 4 VIP, textures, command processor..)) Each time irq happens the handler needs to acknowledge it or the system will hang (it will keep entering the handler). Not to mention: how do I behave nicely w.r.t. other DMA transfers ? Lock them, flush queues, etc. ? At the moment I just want a hacked Xserver that does a DMA transfer from video memory into plain RAM. Or an Xserver with usermode app that does DMA transfer - I don't care. ___ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
Re: [Dri-devel] Using drm (fwd)
On Wed, Oct 10, 2001 at 05:13:40PM -0400, [EMAIL PROTECTED] wrote: So, can anyone answer any of the questions below, or do I have to write drm for multimedia ? The DRM is an architecture for accessing hardware directly. What functions are implemented in any given kernel module is driven by the requirements of the applications running on top of it. That's typically OpenGL at that point. So, most of the drivers are not going to have a function call to support your arbitrary DMA. You don't need to write a drm for multimedia you need to add the hooks you require into the exsting kernel modules for various graphics cards. When do you do this, be careful to consider the security implications. Make sure it can't be used to read or write things that it shouldn't. Also make sure it cooperates with the existing driver in the way it uses memory on the card, the state it leaves the card in after its operations, etc. - |Daryll ___ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
Re: [Dri-devel] Using drm (fwd)
On Wed, 10 Oct 2001, Daryll Strauss wrote: On Wed, Oct 10, 2001 at 05:13:40PM -0400, [EMAIL PROTECTED] wrote: So, can anyone answer any of the questions below, or do I have to write drm for multimedia ? The DRM is an architecture for accessing hardware directly. What functions are implemented in any given kernel module is driven by the requirements of the applications running on top of it. That's typically OpenGL at that point. Daryll, did you read the questions ? I am asking specific things about drm interface. Like what drm handles mean, for example. So, most of the drivers are not going to have a function call to support your arbitrary DMA. I am not interested in most drivers. Heck, I am not even looking for that function. I want to know what can I do with the buffer I allocated using drm. Now, I aprreciate your desire to provide some advice, but I am not interested in general considerations of writing a DMA driver. I want to know answers to specific questions, like What AGP Offset is used for ? it is not specific to any card, it is not specific to what I am trying to do. Can anyone answer it ? Vladimir Dergachev You don't need to write a drm for multimedia you need to add the hooks you require into the exsting kernel modules for various graphics cards. When do you do this, be careful to consider the security implications. Make sure it can't be used to read or write things that it shouldn't. Also make sure it cooperates with the existing driver in the way it uses memory on the card, the state it leaves the card in after its operations, etc. - |Daryll ___ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
Re: [Dri-devel] Using drm (fwd)
Finally, someone who knows the stuff :)) No, there is no such variable, but this phrase I plucked from the comment. Here is an example from radeon.h: /* CP vertex/indirect buffer data */ unsigned long bufStart;/* Offset into AGP space */ drmHandle bufHandle; /* Handle from drmAddMap */ drmSize bufMapSize; /* Size of map */ int bufSize; /* Size of buffers (in MB) */ unsigned char *buf;/* Map */ int bufNumBufs; /* Number of buffers */ drmBufMapPtr buffers; /* Buffer map */ Now, from these I guess that *buf is where I can access the data directly for Xserver. bufSize is the size of the thing - does it have to be in MB ? Or just page-aligned is fine ? bufStart - what do I use this for ? Can I use it to reference data in the buffer or do I have to add or subtract a magic number from it before writing into card's registers ? (and to answer your questions: I have made a copy of the same fields /with buf replaced with capture and allocated space.. nothing seems to crash.., 3d workds, 1mb is reserved someplace. /) I'll check up give you proper answers in a sec. However, it sounds like you're just looking to allocate a buffer of a meg or two on the card somewhere and use that for some purpose. If so, the 3d drivers are doing this all the time - to hold textures. You should be able to do the same thing - just grab a meg or two of texture memory and use that for your purposes. You'll need a trick or two to stop others grabbing it back when resources run low, but it is doable without modifying any kernel structures. Have a look at the files in lib/GL/mesa/src/drv/XYZ/*_tex*.[ch] and in particular functions like i810UploadTexImages() which scan the LRU and allocate memory. Keith _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com ___ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
Re: [Dri-devel] Using drm (fwd)
On Wed, 10 Oct 2001, Keith Whitwell wrote: Finally, someone who knows the stuff :)) No, there is no such variable, but this phrase I plucked from the comment. Here is an example from radeon.h: /* CP vertex/indirect buffer data */ unsigned long bufStart;/* Offset into AGP space */ drmHandle bufHandle; /* Handle from drmAddMap */ drmSize bufMapSize; /* Size of map */ int bufSize; /* Size of buffers (in MB) */ unsigned char *buf;/* Map */ int bufNumBufs; /* Number of buffers */ drmBufMapPtr buffers; /* Buffer map */ Now, from these I guess that *buf is where I can access the data directly for Xserver. bufSize is the size of the thing - does it have to be in MB ? Or just page-aligned is fine ? bufStart - what do I use this for ? Can I use it to reference data in the buffer or do I have to add or subtract a magic number from it before writing into card's registers ? (and to answer your questions: I have made a copy of the same fields /with buf replaced with capture and allocated space.. nothing seems to crash.., 3d workds, 1mb is reserved someplace. /) I'll check up give you proper answers in a sec. However, it sounds like you're just looking to allocate a buffer of a meg or two on the card somewhere and use that for some purpose. If so, the 3d drivers are doing this all the time - to hold textures. You should be able to do the same thing - just grab a meg or two of texture memory and use that for your purposes. You'll need a trick or two to stop others grabbing it back when No, no, I have no trouble allocating RAM. I don't know what to do with it next. I understand how scatter-gather works from looking at bt848 driver. I believe I know the generalities of PCI GART and AGP GART for ATI cards. The problem is I don't understand the specifics. Here is a more involved explanation (all for Radeon as this is what I have plugged in now, besides the docs are more thorough): There is a DMA_VIP0_TABLE_ADDR which accepts a 32 bit address of a table of commands for DMA transfer. Looking at the docs it seems that the transfer is initiated by writing the total number of bytes to transfer in VIPH_CH0_SBCNT. Now, I know the format of the table. But, when I try writing the physical address of the page to make the transfer nothing (useful) happens. So, I guess it goes thru some kind of translation. But which ? Both PCI GART and AGP GART are supposed to straighten memory by themselves so an extra indirect should not be necessary. Furthermore, which addresses need to be written in the table - physical or not ? Now, I could have tried all combinations, except that I don't even know that I am using the right register. There are several DMA engines in the card: 4 VIP ones, GUI, and others. The bmaster example uses GUI to transfer image into main memory, but there is no example of transfer back. Now, the decoder chip is located on VIP bus (which is only one for the whole card), but there are 4 VIP DMA channels with cryptic statement of only 2 DMA transfers could be active in the queue in the same time. Does that mean 2 transfers from VIP devices or one VIP and one 3d I don't know either. As you can see this multiplies the choices significantly. So I want to reduce them by eliminating guesswork from address things. Which brings back the question about AGP offset - what is this ? thanks Vladimir Dergachev PS And, in case it helps, here is a list of things I already tried: standalone kernel module, with ram allocated by rvmalloc from bt848. It seems to both work and not. I see address changing in the DMA status registers, but I don't get End of DMA interrupts. And I don't get any data in the buffers. No lockups though. I tried allocating ram using drm. I can allocate it fine. I don't know what to do with it next (as I can get to physical addresses from within X to form a DMA transfer table. And I don't see any code in X making such a table). resources run low, but it is doable without modifying any kernel structures. Have a look at the files in lib/GL/mesa/src/drv/XYZ/*_tex*.[ch] and in particular functions like i810UploadTexImages() which scan the LRU and allocate memory. Keith _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com ___ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
