From: Chris Wilson Date: Thu, 23 Dec 2010 10:40:38 +0000 (+0000) Subject: agp/intel: Flush the chipset write buffers when changing GTT base X-Git-Tag: firefly_0821_release~7613^2~3044^2~2^2~26 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c97689d8860f086125e7ff9cd730027a0057ca4f;p=firefly-linux-kernel-4.4.55.git agp/intel: Flush the chipset write buffers when changing GTT base Flush the chipset write buffers before and after adjusting the GTT base register, just in case. We only modify this value upon initialisation (boot and resume) so there should be no outstanding writes, however there are always those persistent PGTBL_ER that keep getting reported upon resume. Signed-off-by: Chris Wilson --- diff --git a/drivers/char/agp/intel-agp.h b/drivers/char/agp/intel-agp.h index 010e3defd6c3..c195bfeade11 100644 --- a/drivers/char/agp/intel-agp.h +++ b/drivers/char/agp/intel-agp.h @@ -94,6 +94,8 @@ #define G4x_GMCH_SIZE_VT_1_5M (0xa << 8) #define G4x_GMCH_SIZE_VT_2M (0xc << 8) +#define GFX_FLSH_CNTL 0x2170 /* 915+ */ + #define I810_DRAM_CTL 0x3000 #define I810_DRAM_ROW_0 0x00000001 #define I810_DRAM_ROW_0_SDRAM 0x00000001 diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c index 356f73e0d17e..da8161806f39 100644 --- a/drivers/char/agp/intel-gtt.c +++ b/drivers/char/agp/intel-gtt.c @@ -814,6 +814,12 @@ static bool intel_enable_gtt(void) } } + /* On the resume path we may be adjusting the PGTBL value, so + * be paranoid and flush all chipset write buffers... + */ + if (INTEL_GTT_GEN >= 3) + writel(0, intel_private.registers+GFX_FLSH_CNTL); + reg = intel_private.registers+I810_PGETBL_CTL; writel(intel_private.PGETBL_save, reg); if (HAS_PGTBL_EN && (readl(reg) & I810_PGETBL_ENABLED) == 0) { @@ -823,6 +829,9 @@ static bool intel_enable_gtt(void) return false; } + if (INTEL_GTT_GEN >= 3) + writel(0, intel_private.registers+GFX_FLSH_CNTL); + return true; }