Hi
Am 03.05.20 um 17:42 schrieb Sam Ravnborg:
> Hi Thomas.
>
> On Wed, Apr 29, 2020 at 04:32:31PM +0200, Thomas Zimmermann wrote:
>> The framebuffer's pitch is now set in mgag200_set_offset().
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
>
> I failed to follow this code.
Is it because of the line-offset calculation? MGAs want offsets in
multiples of pixels, not bytes, and that factor depends on the value of
cpp. I guess putting the calculation into a separate function will help
with readability.
>
>> ---
>> drivers/gpu/drm/mgag200/mgag200_mode.c | 41 +++++++++++++++++---------
>> 1 file changed, 27 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
>> index 92dee31f16c42..eb83e471d72fc 100644
>> --- a/drivers/gpu/drm/mgag200/mgag200_mode.c
>> +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
>> @@ -1003,6 +1003,32 @@ static void mgag200_set_mode_regs(struct mga_device *mdev,
>> mga_crtc_set_plls(mdev, mode->clock);
>> }
>>
>> +static void mgag200_set_offset(struct mga_device *mdev,
>> + const struct drm_framebuffer *fb)
>> +{
>> + unsigned int offset;
>> + uint8_t crtc13, crtcext0;
>> + u8 bppshift;
>> +
>> + bppshift = mdev->bpp_shifts[fb->format->cpp[0] - 1];
> Hmm, use of cpp is deprecated. But is continue to be used all over.
I try to move code without modifying it too much. Replacing cpp with
some newer interface would obfuscate the moving to some extend. It's
always a balancing act.
>
>> +
>> + offset = fb->pitches[0] / fb->format->cpp[0];
>> + if (fb->format->cpp[0] * 8 == 24)
>> + offset = (offset * 3) >> (4 - bppshift);
>> + else
>> + offset = offset >> (4 - bppshift);
>> +
>> + RREG_ECRT(0, crtcext0);
>> +
>> + crtc13 = offset & 0xff;
>> +
>> + crtcext0 &= ~GENMASK(5, 4);
>> + crtcext0 |= (offset & GENMASK(9, 8)) >> 4;
> Lot's of hardcoded numbers.
> Could the reg file include these so you had more readable defined names?
Sure.
Best regards
Thomas
>
>> +
>> + WREG_CRT(0x13, crtc13);
>> + WREG_ECRT(0x00, crtcext0);
>> +}
>> +
>> static int mga_crtc_mode_set(struct drm_crtc *crtc,
>> struct drm_display_mode *mode,
>> struct drm_display_mode *adjusted_mode,
>> @@ -1011,7 +1037,6 @@ static int mga_crtc_mode_set(struct drm_crtc *crtc,
>> struct drm_device *dev = crtc->dev;
>> struct mga_device *mdev = dev->dev_private;
>> const struct drm_framebuffer *fb = crtc->primary->fb;
>> - int pitch;
>> int option = 0, option2 = 0;
>> int i;
>> unsigned char misc = 0;
>> @@ -1122,12 +1147,6 @@ static int mga_crtc_mode_set(struct drm_crtc *crtc,
>> WREG_SEQ(3, 0);
>> WREG_SEQ(4, 0xe);
>>
>> - pitch = fb->pitches[0] / fb->format->cpp[0];
>> - if (fb->format->cpp[0] * 8 == 24)
>> - pitch = (pitch * 3) >> (4 - bppshift);
>> - else
>> - pitch = pitch >> (4 - bppshift);
>> -
>> WREG_GFX(0, 0);
>> WREG_GFX(1, 0);
>> WREG_GFX(2, 0);
>> @@ -1144,20 +1163,15 @@ static int mga_crtc_mode_set(struct drm_crtc *crtc,
>> WREG_CRT(13, 0);
>> WREG_CRT(14, 0);
>> WREG_CRT(15, 0);
>> - WREG_CRT(19, pitch & 0xFF);
>> -
>> - ext_vga[0] = 0;
>>
>> /* TODO interlace */
>>
>> - ext_vga[0] |= (pitch & 0x300) >> 4;
>> if (fb->format->cpp[0] * 8 == 24)
>> ext_vga[3] = (((1 << bppshift) * 3) - 1) | 0x80;
>> else
>> ext_vga[3] = ((1 << bppshift) - 1) | 0x80;
>> ext_vga[4] = 0;
>>
>> - WREG_ECRT(0, ext_vga[0]);
>> WREG_ECRT(3, ext_vga[3]);
>> WREG_ECRT(4, ext_vga[4]);
>>
>> @@ -1171,8 +1185,6 @@ static int mga_crtc_mode_set(struct drm_crtc *crtc,
>> WREG_ECRT(6, 0);
>> }
>>
>> - WREG_ECRT(0, ext_vga[0]);
>> -
>> misc = RREG8(MGA_MISC_IN);
>> misc |= MGAREG_MISC_IOADSEL |
>> MGAREG_MISC_RAMMAPEN |
>> @@ -1180,6 +1192,7 @@ static int mga_crtc_mode_set(struct drm_crtc *crtc,
>> WREG8(MGA_MISC_OUT, misc);
>>
>> mga_crtc_do_set_base(mdev, fb, old_fb);
>> + mgag200_set_offset(mdev, fb);
>>
>> mgag200_set_mode_regs(mdev, mode);
>
> Sam
>
--
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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