[PATCH 08/10] drm/gma500: Set page-caching flags in GEM pin/unpin

[Thomas Zimmermann]

Hi

Am 03.10.21 um 00:15 schrieb Patrik Jakobsson:
> On Tue, Sep 28, 2021 at 10:44 AM Thomas Zimmermann <tzimmermann at suse.de> wrote:
>>
>> Caching of the GEM object's backing pages are unrelated to GTT
>> management. Move the respective calls from GTT code to GEM code.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
>> ---
>>   drivers/gpu/drm/gma500/gem.c |  9 ++++++++-
>>   drivers/gpu/drm/gma500/gtt.c | 17 ++---------------
>>   drivers/gpu/drm/gma500/gtt.h |  2 +-
>>   3 files changed, 11 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/gma500/gem.c b/drivers/gpu/drm/gma500/gem.c
>> index 46209e10dcc2..a88d51a3aa2a 100644
>> --- a/drivers/gpu/drm/gma500/gem.c
>> +++ b/drivers/gpu/drm/gma500/gem.c
>> @@ -13,6 +13,8 @@
>>
>>   #include <linux/pagemap.h>
>>
>> +#include <asm/set_memory.h>
>> +
>>   #include <drm/drm.h>
>>   #include <drm/drm_vma_manager.h>
>>
>> @@ -39,7 +41,9 @@ int psb_gem_pin(struct gtt_range *gt)
>>
>>          npages = gt->gem.size / PAGE_SIZE;
>>
>> -       ret = psb_gtt_insert(dev, gt, 0);
>> +       set_pages_array_wc(pages, npages);
>> +
>> +       ret = psb_gtt_insert(dev, gt);
>>          if (ret)
>>                  goto err_drm_gem_put_pages;
>>
>> @@ -80,6 +84,9 @@ void psb_gem_unpin(struct gtt_range *gt)
>>                                       (gpu_base + gt->offset), gt->npage, 0, 0);
>>          psb_gtt_remove(dev, gt);
>>
>> +       /* Reset caching flags */
>> +       set_pages_array_wb(gt->pages, gt->npage);
>> +
>>          drm_gem_put_pages(&gt->gem, gt->pages, true, false);
>>          gt->pages = NULL;
>>
>> diff --git a/drivers/gpu/drm/gma500/gtt.c b/drivers/gpu/drm/gma500/gtt.c
>> index 5d940fdbe6b8..244de618e612 100644
>> --- a/drivers/gpu/drm/gma500/gtt.c
>> +++ b/drivers/gpu/drm/gma500/gtt.c
>> @@ -7,10 +7,6 @@
>>    *         Alan Cox <alan at linux.intel.com>
>>    */
>>
>> -#include <linux/shmem_fs.h>
>> -
>> -#include <asm/set_memory.h>
>> -
>>   #include "psb_drv.h"
>>
>>
>> @@ -92,17 +88,15 @@ static u32 __iomem *psb_gtt_entry(struct drm_device *dev, struct gtt_range *r)
>>    *     psb_gtt_insert  -       put an object into the GTT
>>    *     @dev: our DRM device
>>    *     @r: our GTT range
>> - *     @resume: on resume
>>    *
>>    *     Take our preallocated GTT range and insert the GEM object into
>>    *     the GTT. This is protected via the gtt mutex which the caller
>>    *     must hold.
>>    */
>> -int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r, int resume)
>> +int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r)
>>   {
>>          u32 __iomem *gtt_slot;
>>          u32 pte;
>> -       struct page **pages;
>>          int i;
>>
>>          if (r->pages == NULL) {
>> @@ -113,12 +107,6 @@ int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r, int resume)
>>          WARN_ON(r->stolen);     /* refcount these maybe ? */
>>
>>          gtt_slot = psb_gtt_entry(dev, r);
>> -       pages = r->pages;
>> -
>> -       if (!resume) {
>> -               /* Make sure changes are visible to the GPU */
>> -               set_pages_array_wc(pages, r->npage);
>> -       }
> 
> I don't quite remember why we have this but I suspect something bad
> happened when setting WC on a page with WC already set. Did you try
> hibernation?

I took the code as-is. I guess that reading back BO memory with read 
caching enabled didn't work well when fbdev acceleration was still around.

Best regards
Thomas

> 
>>
>>          /* Write our page entries into the GTT itself */
>>          for (i = 0; i < r->npage; i++) {
>> @@ -158,7 +146,6 @@ void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r)
>>          for (i = 0; i < r->npage; i++)
>>                  iowrite32(pte, gtt_slot++);
>>          ioread32(gtt_slot - 1);
>> -       set_pages_array_wb(r->pages, r->npage);
>>   }
>>
>>   static void psb_gtt_alloc(struct drm_device *dev)
>> @@ -349,7 +336,7 @@ int psb_gtt_restore(struct drm_device *dev)
>>          while (r != NULL) {
>>                  range = container_of(r, struct gtt_range, resource);
>>                  if (range->pages) {
>> -                       psb_gtt_insert(dev, range, 1);
>> +                       psb_gtt_insert(dev, range);
>>                          size += range->resource.end - range->resource.start;
>>                          restored++;
>>                  }
>> diff --git a/drivers/gpu/drm/gma500/gtt.h b/drivers/gpu/drm/gma500/gtt.h
>> index 459a03141e8b..7af71617e0c5 100644
>> --- a/drivers/gpu/drm/gma500/gtt.h
>> +++ b/drivers/gpu/drm/gma500/gtt.h
>> @@ -49,7 +49,7 @@ int psb_gtt_allocate_resource(struct drm_psb_private *pdev, struct resource *res
>>                                const char *name, resource_size_t size, resource_size_t align,
>>                                bool stolen, u32 offset[static 1]);
>>
>> -int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r, int resume);
>> +int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r);
>>   void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r);
>>
>>   #endif
>> --
>> 2.33.0
>>

-- 
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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