[PATCH] drm/mgag200: Don't set <rammapen> in MISC

[Thomas Zimmermann]

Hi

Am 17.06.20 um 11:22 schrieb Rong Chen:
> On Wed, Jun 17, 2020 at 08:28:02AM +0200, Thomas Zimmermann wrote:
>> Hi Emil
>>
>> Am 16.06.20 um 17:14 schrieb Emil Velikov:
>>> Hi Thomas,
>>>
>>> On Tue, 16 Jun 2020 at 15:26, Thomas Zimmermann <tzimmermann at suse.de> wrote:
>>>>
>>>> The original modesetting code set MISC to 0x2d, which is <hpgoddev>,
>>>> <clksel> and <ioaddsel>
>>>>
>>>> With the conversion to atomic modesetting, <rammapen> accidentally
>>>> got enabled as well. Revert this change and initialize MISC with a
>>>> constant value of <hgoddev> and <ioaddsel>. The <clksel> bits are set
>>>> in mga_crtc_set_plls(), sync flags are set in mgag200_set_mode_regs().
>>>>
>>>
>>> Let's keep the remove (restoring original functionality) and rename
>>> (cosmetics) separate patches. The read has also disappeared, which
>>> should be safe although might be better on it's own.
>>
>> I'm waiting for Rong Chen's performance results on this patch. Moving
>> the rename into a separate patch makes sense, but removing the read is
>> part of restoring the original behavior. I think it should be in this
>> patch. Maybe I can write a better commit message to highlight the change.
>>
> 
> Hi Thomas,
> 
> I tested the patch based on previous patch series, it seems doesn't take
> effect, and commit 39fb72816c4ee brings a larger regression when
> comparing to commit caac4dda44f37:

Thanks for testing!

I still don't understand these numbers, but are you sure that
e44e907dd8f93 is really the regression?

It would make sense that 39fb72816c4ee has an impact on performance, as
it changes memory management and the way the driver updates the display.
I'll take a closer look at that patch and maybe send out an update.

Best regards
Thomas

> 
> 4606edf870927 drm/mgag200: Don't set <rammapen> in MISC                                              3 3 3
> 39fb72816c4ee drm/mgag200: Replace VRAM helpers with SHMEM helpers                                   3 22
> caac4dda44f37 drm/mgag200: Convert to simple KMS helper                                              238 233 240 234 239
> 4b11c90431108 drm/mgag200: Use simple-display data structures                                        35 34 34 34
> db22c903c9322 drm/mgag200: Remove out-commented suspend/resume helpers                               34 34
> 87d4880d2aeb5 drm/mgag200: Move register initialization into separate function                       35
> 0c51726f95396 drm/mgag200: Move hiprilvl setting into separate functions                             35
> 8078e8b182e73 drm/mgag200: Set primary plane's format in separate helper function                    35
> 19f7b409d95b7 drm/mgag200: Set pitch in a separate helper function                                   35 34
> 9b9a363828c60 drm/mgag200: Update mode registers after plane registers                               34
> e44e907dd8f93 drm/mgag200: Split MISC register update into PLL selection, SYNC and I/O               34 34 34 34
> bef2303526adb drm/mgag200: Move mode-setting code into separate helper function                      97 97
> 5cd8460e81e8f drm/mgag200: Clean up mga_crtc_do_set_base()                                           96
> 0671ca8c559ba drm/mgag200: Clean up mga_set_start_address()
> e82c8969a2474 drm/mgag200: Remove HW cursor                                                          96
> 
> Best Regards,
> Rong Chen
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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