[PATCH 3/4] drm/mgag200: Add workaround for HW that does not support 'startadd'

[John Donnelly]

Hi ,

See below ,


> On Nov 26, 2019, at 3:50 AM, Thomas Zimmermann <tzimmermann at suse.de> wrote:
> 
> Hi
> 
> Am 26.11.19 um 10:37 schrieb Daniel Vetter:
>> On Tue, Nov 26, 2019 at 08:25:44AM +0100, Thomas Zimmermann wrote:
>>> There's at least one system that does not interpret the value of
>>> the device's 'startadd' field correctly, which leads to incorrectly
>>> displayed scanout buffers. Always placing the active scanout buffer
>>> at offset 0 works around the problem.
>>> 
>>> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
>>> Reported-by: John Donnelly <john.p.donnelly at oracle.com>
>>> Link: https://gitlab.freedesktop.org/drm/misc/issues/7
>> 
>> Tested-by: John Donnelly <john.p.donnelly at oracle.com>
>> 
>> (Not quite this patch, but pretty much the logic, so counts).
>> 
>> Fixes: 81da87f63a1e ("drm: Replace drm_gem_vram_push_to_system() with kunmap + unpin")
>> Cc: <stable at vger.kernel.org> # v5.3+
>> 
>> Also you need the stable line on both prep patches too. For next time
>> around,
>> 
>> $ dim fixes 81da87f63a1e
>> 
>> will generate all the stuff you need, including a good set of suggested
>> Cc: you should have.
>> 
>> On the first 3 patches, with all that stuff added:
>> 
>> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> 
> Thanks for the review.
> 
> Sorry for leaving out some of the tags. I wanted to wait for feedback
> before adding tested-by, fixes, stable. I'll split off patch 4 from the
> series and get 1 to 3 merged ASAP.
> 
> Best regards
> Thomas
> 
>> 
>> Please push these to drm-misc-next-fixes so they get backported as quickly
>> as possible.
>> -Daniel
>> 
>>> ---
>>> drivers/gpu/drm/mgag200/mgag200_drv.c | 36 ++++++++++++++++++++++++++-
>>> drivers/gpu/drm/mgag200/mgag200_drv.h |  3 +++
>>> 2 files changed, 38 insertions(+), 1 deletion(-)
>>> 
>>> diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
>>> index 397f8b0a9af8..d43951caeea0 100644
>>> --- a/drivers/gpu/drm/mgag200/mgag200_drv.c
>>> +++ b/drivers/gpu/drm/mgag200/mgag200_drv.c
>>> @@ -30,6 +30,8 @@ module_param_named(modeset, mgag200_modeset, int, 0400);
>>> static struct drm_driver driver;
>>> 
>>> static const struct pci_device_id pciidlist[] = {
>>> +	{ PCI_VENDOR_ID_MATROX, 0x522, PCI_VENDOR_ID_SUN, 0x4852, 0, 0,
>>> +		G200_SE_A | MGAG200_FLAG_HW_BUG_NO_STARTADD},



I will have an additional list of vendor IDs (0x4852)  I will provide in a follow up patch shortly .  This fixes only 1 flavor  of server.


Thank you .






>>> 	{ PCI_VENDOR_ID_MATROX, 0x522, PCI_ANY_ID, PCI_ANY_ID, 0, 0, G200_SE_A },
>>> 	{ PCI_VENDOR_ID_MATROX, 0x524, PCI_ANY_ID, PCI_ANY_ID, 0, 0, G200_SE_B },
>>> 	{ PCI_VENDOR_ID_MATROX, 0x530, PCI_ANY_ID, PCI_ANY_ID, 0, 0, G200_EV },
>>> @@ -60,6 +62,35 @@ static void mga_pci_remove(struct pci_dev *pdev)
>>> 
>>> DEFINE_DRM_GEM_FOPS(mgag200_driver_fops);
>>> 
>>> +static bool mgag200_pin_bo_at_0(const struct mga_device *mdev)
>>> +{
>>> +	return mdev->flags & MGAG200_FLAG_HW_BUG_NO_STARTADD;
>>> +}
>>> +
>>> +int mgag200_driver_dumb_create(struct drm_file *file,
>>> +			       struct drm_device *dev,
>>> +			       struct drm_mode_create_dumb *args)
>>> +{
>>> +	struct mga_device *mdev = dev->dev_private;
>>> +	unsigned long pg_align;
>>> +
>>> +	if (WARN_ONCE(!dev->vram_mm, "VRAM MM not initialized"))
>>> +		return -EINVAL;
>>> +
>>> +	pg_align = 0ul;
>>> +
>>> +	/*
>>> +	 * Aligning scanout buffers to the size of the video ram forces
>>> +	 * placement at offset 0. Works around a bug where HW does not
>>> +	 * respect 'startadd' field.
>>> +	 */
>>> +	if (mgag200_pin_bo_at_0(mdev))
>>> +		pg_align = PFN_UP(mdev->mc.vram_size);
>>> +
>>> +	return drm_gem_vram_fill_create_dumb(file, dev, &dev->vram_mm->bdev,
>>> +					     pg_align, false, args);
>>> +}
>>> +
>>> static struct drm_driver driver = {
>>> 	.driver_features = DRIVER_GEM | DRIVER_MODESET,
>>> 	.load = mgag200_driver_load,
>>> @@ -71,7 +102,10 @@ static struct drm_driver driver = {
>>> 	.major = DRIVER_MAJOR,
>>> 	.minor = DRIVER_MINOR,
>>> 	.patchlevel = DRIVER_PATCHLEVEL,
>>> -	DRM_GEM_VRAM_DRIVER
>>> +	.debugfs_init = drm_vram_mm_debugfs_init,
>>> +	.dumb_create = mgag200_driver_dumb_create,
>>> +	.dumb_map_offset = drm_gem_vram_driver_dumb_mmap_offset,
>>> +	.gem_prime_mmap = drm_gem_prime_mmap,
>>> };
>>> 
>>> static struct pci_driver mgag200_pci_driver = {
>>> diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.h b/drivers/gpu/drm/mgag200/mgag200_drv.h
>>> index 4b4f9ce74a84..aa32aad222c2 100644
>>> --- a/drivers/gpu/drm/mgag200/mgag200_drv.h
>>> +++ b/drivers/gpu/drm/mgag200/mgag200_drv.h
>>> @@ -150,6 +150,9 @@ enum mga_type {
>>> 	G200_EW3,
>>> };
>>> 
>>> +/* HW does not handle 'startadd' field correct. */
>>> +#define MGAG200_FLAG_HW_BUG_NO_STARTADD	(1ul << 8)
>>> +
>>> #define MGAG200_TYPE_MASK	(0x000000ff)
>>> #define MGAG200_FLAG_MASK	(0x00ffff00)
>>> 
>>> -- 
>>> 2.23.0
>>> 
>> 
> 
> -- 
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
> Geschäftsführer: Felix Imendörffer
>